The short answer is "yes". Those judgments mentioned in 2 Pet. 2:4 and Jude 1:6 really happened. But, they were not the judgments most people assume.
The true author of the Bible is the Holy Spirit. He used the agency of men to put His word into the world. The men wrote His words on mediums of papyrus scrolls, and then on vellum parchment. The "authors" we like to argue over... who wrote the book of Hebrews, etc... were God's secretaries, his agents. The Holy Spirit spoke to the men, and the men wrote for Him.
"20 Knowing this first, that no prophecy of the scripture is of any private interpretation. 21 For the prophecy came not in old time by the will of man: but holy men of God spake as they were moved by the Holy Ghost." (2 Pet. 1:20-21, KJV)
The men were the recipients of the words of the Holy Spirit, the messengers that He chose to use, to speak through. Jude was also moved by the Holy Spirit, and he did not quote from that so-called Book of Enoch that so many people seem to find thrilling.
The Holy Spirit knew that Enoch had prophesied of wicked men who would face God's judgment. Just because He named a real man who prophesied, the seventh son from Adam, does not mean that He quoted from a work of fiction.
May I suggest that a piece of fiction most likely picked selected passages from the word of God to use as props for the purpose of convincing people that the book men created... the Book of Enoch... was true? The Adversary has always seduced men into believing a lie by mixing truths with false information (Gen. 3:1-5).
When we credit the true source of the word of God, the Holy Spirit with having known of Enoch, of having personal knowledge of the seventh man from Adam, is it even necessary to have to justify the mention of Enoch as a prophet of God? The Holy Spirit knew Enoch, and the Holy Spirit is the source author of the book of Jude. Jude was the secretary speaking on behalf of the Holy Spirit.
"And Enoch also, the seventh from Adam, prophesied of these,..." (Jude 1:14, KJV)
It is a simple statement by the Holy Spirit that Enoch prophesied. It is not a quote from the Book of Enoch.
However, the context of both 2 Pet. 2:4 and Jude 1:6 are within the discussion of the judgments that came upon wicked "men".
"For there are certain men crept in unawares,..." (Jude 1:4, KJV)
"...having saved the people out of the land of Egypt, afterward destroyed them that believed not." (Jude 1:5, KJV)
"Even as Sodom and Gomorrha, and the cities about them..." (Jude 1:7, KJV)
So, in vs 6, between vs 5 and 7 the subject suddenly jumps from wicked men to wicked "angels"? Not hardly. The translation is at fault, and the many commentaries have been deceived by the mysticism injected into the Babylonian and the Jerusalem Talmuds, the Midrash and Mishnah, the mythologies of Greek and Roman paganism, Milton's fictional "Paradise Lost"; in other words the writings of men who ran with their imaginations of "fallen angels" from heaven.
The word "angels" in the English translation is not a translation. It is a transliteration of the Greek "angelos" which means messenger. (See my answer to this question here.) In the OT the original word is the Hebrew "malak" which means messenger. It is the root of Malachi's name, which means "My messenger". Messengers can be either from heaven, or those men who carried God's word to the people on earth... the prophets, the Levitical priests, the judges, the apostles and disciples of the NT. These were all messengers of God.
2 Pet 2:1-3 begins with the false prophets and false teachers among the people....men. 2 Pet. 2:5 - Noah and the old world of the flood...men. 2 Pet. 2:6-8 - Sodom and Gomorrah, ungodly men. 2 Pet. 2:10 - men speaking evil of dignitaries.
But, in the middle of these verses, vs. 4 suddenly changes the context, the subject to heavenly messengers? Again, not hardly!
Notice what happens at 2 Pet. 2:11:
"Whereas angels, which are greater in power and might, bring not railing accusation against them before the Lord." (KJV)
Let's translate that verse correctly...
"Whereas [messengers], which are greater in power and might, bring not railing accusation against them before the Lord."
Why is the verse stressing those messengers that are greater in power and might? Could it be because they are different from those "messengers" (angels) that are in 2 Pet. 2:4? Yes, they definitely are.
The messengers that are greater in power and might are those that are in heaven who face God every single day and know His authority.
"Bless the Lord, ye his angels, that excel in strength, that do his commandments, hearkening unto the voice of his word." (Psa. 103:20, KJV)
The angels / messengers that excel in strength are those that are in heaven! As 2 Pet. 2:11 distinguished those heavenly messengers from those in 2 Pet. 2:4 as being greater in strength, then those messengers in 2 Pet. 2:4, just as those in Jude 6 were speaking of messengers that were of lesser strength...men!
Now, we have the subject matter the same. Both 2 Pet. 2:4, and Jude 1:6 were speaking of wicked men. Those wicked messengers who were supposed to be speaking God's word to the people were men who left their first estate, or their appointed office before God. The context was of old... in the OT. Jude 1:5 spoke of men coming out of the exodus from Egypt, the vs. 7 jumped back in time to Sodom and Gomorrah which came before the Exodus. So, these are not necessarily chronological.
Those men who held appointed offices to teach and speak the word of God.. the Law... were His priests in the temple. Those messengers fell away from God's word, and became insubordinate, and did not do their jobs. The left their first estate - their primary function and task. This is a collective of all those priests / messengers of the Mosaic temple who failed in their duty before God to properly teach His word to the people.
Some suppose this could have been the rebellion of Korah, Dathan, and Abiram of Num. ch. 16 who challenged Moses' leadership. Korah was a Levite, but Dathan and Abiram were sons of Eliab (Num. 16:1).
"31 And it came to pass, as he had made an end of speaking all these words, that the ground clave asunder that was under them:
32 And the earth opened her mouth, and swallowed them up, and their houses, and all the men that appertained unto Korah, and all their goods.
33 They, and all that appertained to them, went down alive into the pit, and the earth closed upon them: and they perished from among the congregation." (Num. 16:31-33, KJV)
As 2 Pet. 2:4 and Jude 1:6 separate the earthly messengers as having been appointed to offices before God, then the only one of these that would qualify would have been Korah. And, as Korah and his company was set apart to be ministers in the tabernacle and ministers to the congregation (Num. 16:9), then this event is a possible answer.
However, I believe the fullness of 2 Pet. 2:4 and Jude 1:6 would include all of the Levitical priesthood who ever turned from God, and who led the people astray. They collectively would all fit into this judgment; and that all of them would have been assigned to the grave - Sheol.
2 Pet. 2:4, and Jude 1:6 did happen. The "angels" should properly be translated as "messengers" and the context governs the meaning as earthly messengers...men, specifically wicked men who turned from God and misled the people.
Yes, 2 Pet. 2:4 and Jude 1:6 did really happen.
The whole concept that the heavenly angels / messengers who face God every day, who know God's rule and authority is real; the idea that these "angels" could fall out of heaven, could be "fallen angels" is slandering those messengers of greater strength and power! It is the earthly messengers...men... who have problems following God's instructions. These earthly messengers are the subject of 2 Pet. 2:4, and Jude 1:6.
Supporting work regarding the book of Enoch and the translation of Enoch and Elijah at my blog ShreddingTheVeil here, here, here, and here.
All bold emphasis is mine.