An acquaintance of ours makes a fine point:

There's no particular reason that different forms of disagreement with Church's understanding of human nature should be mutually consistent, and yet I can't help but be struck by the irony: in an era when some people are arguing that homosexual acts should be approved because gay and lesbian people are "born that way," other people (or occasionally the same people, just depending on whether the tides are high or low) are arguing that biological maleness and femaleness are basically irrelevant to what sort of people we are. To the latter camp, suggesting otherwise is the great sin of essentialism. "Biology is not destiny" was one of the classic feminist slogans.

Think about it.

In fact, I would go so far as to say that there is every reason to believe that those who oppose Catholic teaching are actually incapable of making "mutually consistent" arguments for their defence of popular vices. The rejection of "Catholic teaching" is simply the rejection of rationality and even the notion of logical consistency must be jettisoned in order to achieve this.