My understanding is that the sin God singles out as heinous above all others is the sin of idolatry. This is demonstrated in the ten commandments and in Christ's summary of the law in the two greatest commandments. In the ancient Middle East, sexual immorality was entwined with the worship of false gods and the seeking of "spiritual power" by those means. Thus the penalty of capitol punishment. My understanding is that this is what the men of Sodom wanted with the angels and why God annihilated the place. His insructions to Israel to completely exterminate certain enemies in battel was for the same reason--they were intensely idolatrous nations, with accompanying sexual worship, human sacrifice, etc.
While what you say above is quite true, it is interesting to note that in the NT God singles out
greed as idolatry. But, He does not call for the death of the greedy. He does not, to my knowledge, single out homosexuality as idolatry, but he does say that it is worthy of death.
I suspect that the reasoning behind Paul's statement is that man is the highest point of all creation because he bears the Imago Dei, even though it was marred by the fall. If I am right, this is why he places such a severe condemnation upon homosexuality. "Male and female created he them".
Thomas Maddux