It's a much smaller business than gender conformity. The sometimes-richest-man-in-the-world, Bernard Arnault, has made his fortune largely through exploiting gender conformity and gender dimorphism expressed through fashion.

Some things are social constructs; some aren't. Where postmodernism gets into trouble is placing too much emphasis on the idea that everything is a social construct. Clearly some aspects of gender--e.g. those that aren't stable across cultures or time--are social constructs. Concluding that therefore everything is purely a social construct seems much more like sloppy thinking than an intentional attempt to psychologically dominate others. We see the same kind of counter-rational oversimplification in numerous other human affairs (particularly amusing and/or discouraging in climate change, where people who deny it will say "this is a record cold summer, climate change is a hoax!" and those who are climate doomers will say "this is a record hot summer, this proves climate change is real and will kill us all!")

The position of trans activists regarding acceptance of stated gender does, when taken to that limit, mean that we have to accept someone who decided fifteen minutes ago, for whatever reason, to declare a different gender as that different gender, but to me this seems a reaction pushing to the exact opposite extreme of those who deny that there is something profoundly (not whimsically) different about people who strongly, viscerally feel that they're in the wrong body, consistently, throughout their whole lives, demonstrate this and display prototypical behaviors of the opposite gender. The thing is, you don't have to have any difficult arguments about mental states if either (1) whatever you say or feel is the truth, or (2) nothing that you say or feel matters at all. Postmodern style trans activism adopts (1) to get into argumentative easy-mode, while the strident anti-trans folks adopt (2) for their own easy mode.

But I don't see absurdity as the point. Objective reality is caught in the crossfire; it’s not the target.

After all, why go first for something that people often feel very strongly about? If you want to undermine objective reality, go for counterfactuals that people can easily give up. ("Yeah, really, I don't care how many lights there are. I'll just say five. Whatever.")