Excellent question!
I will here present some points that lead me to view this Ezekiel reference to Sodom as not a viable passage from which to assess the sin leading to the destruction of the Sodom in Genesis. I see 2 primary ways of understanding Ezekiel's use of the name "Sodom". Each understanding has its own heading after the background points to hold in view.
Important points about the passage (Background):
- Exekiel is commanded to speak these things to Jerusalem. This focuses the statements on the city of Jerusalem, contemporary of Ezekiel.
Ezekiel 16:3 and say, ‘This is what the Sovereign Lord says to Jerusalem:
- Ezekiel references the early Genesis roots of the region. In this Genesis reference is also the first reference to Sodom, but no mention of Samaria with that name.
Ezekiel 16:3b Your ancestry and birth were in the land of the Canaanites; your father was an Amorite and your mother a Hittite.
Genesis 10:15 Canaan was the father of Sidon his firstborn, and of the Hittites, 16 Jebusites, Amorites,...
Continuing in Ezekiel 16:3-45, in NASB an apparently allegorical history is given of Jerusalem.
Then the sisters are introduced- Samaria, the older sister and Sodom the younger sister. They are referenced as being less evil than Jerusalem (even only half as evil). The sins of Jerusalem listed here are clearly allegorical with possibly the most lewd language found in the scriptures. Then Ezekiel, in stark contrast, lists the sins of Sodom as being non-sexual, although he does reference the Lord as saying that Sodom was "doing destesteble things before me" (note that a full study of "before the LORD" is important).
Given the numerous other references and comparisons to historical Sodom found in the Prophets, this Ezekiel passage would be "extra" information as it is the only reference to oppression of the poor as being the sin of Sodom. In another question I listed a longer analysis including a listing of every reference in the Nicean Canon to Sodom with a categorization as to whether that reference was a reference to cause or results. In other words, was the reference used to compare to the results of Sodom (destruction) or the cause of Sodom's destruction (the situation that precipitated the destruction). In that analysis the results appeared to indicate that the cause was turning to other gods, as summarized from the inferential references to Sodom. (that posting is currently on Hold as it was voted as Off-Topic)
First Possible Understanding
It may be that when Ezekiel is referring to Sodom and Samaria, he is refering to the geographic areas to the south and north of Jerusalem and the peoples living there in the contemporary times of Ezekiel.
Given that the prophecy is about the Jerusalem that is the contemporary of Ezekiel, a path of logic would indicate that the sisters are also contemporaries. Possibly meaning the regions that are to the north and south of Jerusalem. This approach certainly makes the promise of verse 53 (restoration to Sodom and Samaria) easier to incorporate into our overall understanding.
Second Possible Understanding
It can also be construed that the Jerusalem in focus is the Salem of the Genesis 13 account (contemporary to the annhilated Sodom) and the whole prophecy is not about Israel per se. Rather, the focus is the overall plan from the beginning of time. In this view, we must keep the allegory intact - the reference to the sins of Sodom are as allegorical as the listed sins Jerusalem. In other words, just as Jerusalem's sin is lusting after the genitals of Egypt, Sodom's sin was being proud and not caring for those in need.
Summary
Either way, the sins listed for Sodom are not the specific sins for the historical Sodom of Genesis.
As to your end question: was Judah's sin worse than Sodom's? This is an extremely important question and one that I feel can be answered, but takes a different approach than looking at sexual sin. Judah and Israel (southern and northern divided Kingdoms) both have histories of sexual sin, some even quite parallel to Sodom, yet without the no-delay execution of complete destruction. I feel that this is yet another example that our Lord has given us so that we might begin to see the real battle.
Blessings to all.