In Judges 19 we read,
While they were enjoying themselves, some of the wicked men of the city surrounded the house. Pounding on the door, they shouted to the old man who owned the house, “Bring out the man who came to your house so we can have sex with him.”
23 The owner of the house went outside and said to them, “No, my friends, don’t be so vile. Since this man is my guest, don’t do this outrageous thing. 24 Look, here is my virgin daughter, and his concubine. I will bring them out to you now, and you can use them and do to them whatever you wish. But as for this man, don’t do such an outrageous thing.”
25 But the men would not listen to him. So the man took his concubine and sent her outside to them, and they raped her and abused her throughout the night, and at dawn they let her go.
This abhorrent act is also found in Genesis 19 (Lot and the Sodomites).
I think it is obvious from the narrative that the wicked youngsters were not interested in gratifying themselves (through rape), if this was the case why did they insist on raping the foreigner when the old man offered his daughter instead. If so, my question is what was indeed their objective?