I think abominations were especially harmful biologically, socially, psychologically, or spiritually. And when you think about it, we know the biological damage of homosexuality. Using the logic of Romans 1, it is gross self-worship, and as you've said, it is so obviously unnatural.
Now, the argument about all sins being equal is also in error, because I don't think all punishment is equal. In the same way that the bible hints there are different degrees of reward in heaven, I also thinks it hints that about degrees of punishment in hell. All is awful beyond our imagining, so one really has to wonder.
Matthew 11:20-24 “Woe to you, Chorazin. Woe to you, Bethsaida. For if the miracles had occurred in Tyre and Sidon which occurred in you, they would have repented long ago in sackcloth and ashes. Nevertheless I say to you, it shall be more tolerable for Tyre and Sidon in the day of judgment, than for you. And you, Capernaum, will not be exalted to heaven, will you? You shall descend to Hades; for if the miracles had occurred in Sodom which occurred in you, it would have remained to this day. Nevertheless I say to you that it shall be more tolerable for the land of Sodom in the day of judgment, than for you.”
Excellent points, xzins. I’d forgotten those scriptures, but it does appear there are different levels of punishment. Now that I think about it, aren’t teachers held to a higher standard, too? I’ll have to look for those verses.