Genesis does not mention consensual gay sex. If one is entitled to assume that the only people who would try to force themselves on an outsider were people who enjoyed consensual gay sex amongst themselves, then one could make an inference that consensal homosexuality was rampant in Sodom, but I don't think we are entitled to make that assumption.
Ezekiel is consistent with homosexuality, in and of itself, being part of the problem, but it clearly implies that other types of problems existed. So, any attempt to say that homosexuality is the one sin that makes God so angry that he zaps people for it (as opposed to all the other deadly sins), collapses on the basis of Ezekiel.
Jude is probably the best passage for the anti-gay case, but are we entitled to identify perversion with homosexuality? The Sodomites may well have been motivated by sadism, and were intending rape. I consider rape and sadism to be sexual perversions in and of themselves, whether directed toward the same sex or the opposite sex. Sadism and rape also fit better with the passages suggesting that the sin of Sodom was related to arrogance.
Hypothesis: The sin of Sodom was the sin of arrogance on the part of the rich and powerful toward the poor and powerless, which expressed itself in sexual terms through acts of sexual domination, even toward sojourners. Such acts could well have been both homosexual and heterosexual, but the defining feature of this perversion of Sodom was domination, not homosexuality.
Can this hypothesis be refuted?