Though several Bible texts deal with the sin of Sodom, only one text actually attributes a sexual sin to the destroyed city. That text is Jude 7. the fact that it took this long for a Bible writer to actually condemn Sodom for sexual reasons indicates that sex was not a core issue in the destruction of the city. Also notable is the fact that homophobes gather around this text like flies, knowing that it is their license to use Genesis 19 against homosexuals.
But what does Jude 7 really condemn in Sodom? The text says that the city was destroyed for “excessive lust” and that this lust was for “different flesh” (sarkas heteras). Sarkas means “flesh.” Heteras is the word for “different.” Remember that homosexual refers to someone attracted to the same sex and heterosexual refers to those attracted to the different sex. According to Jude the people of Sodom were heterasarxuals — an odd way to describe homosexuals. Clearly, homosexuality is not the lust for “different flesh” described in Jude 7.
Then what is it that Jude condemns in Sodom? The clue is in the previous verse. The sin and punishment of Sodom is like that of the angels in verse 6. These angels did not stay in their high (arkhe) place, but rather abandoned it for an alternative level. 2 Peter 2:4-7 likewise parallels Sodom and these angels, and in verse 10 accuses both groups of defiling passions and spite for proper authority. Because of lust they did not stay in their proper place. Other Jewish works from this period likewise parallel the sin of Sodom and these angels (e.g. Test. Naphtali 3:4-5).
In short, the angels are condemned for lusting after human females (Gen 6:2-4) and the people of Sodom for lusting after the two angels who visited the city. When the angels lusted for humans they left their proper position and authority to have human wives. When the people of Sodom lusted for the two visitors, they desired different (non-human) flesh. It is like an inversion of bestiality in which humans and super-human beings are forbidden to mate.
Notice that the homosexual lust of the men of Sodom paralleled with the heterosexual lust of the angels. Species was more important than gender. Jude, Peter and others ignored the homosexuality in the Sodom story because they were scandalized by sexual relationships between humans and angels. If anything, Jude 7 testifies that homosexuality was certainly not much of a concern when these other issues are at stake.