Except when they aren't. Again, you can ignore all the counterexamples you want, nothing is keeping writers away from whatever subtext they want to give. Alan Moore wasn't any more conservative writing Superman than he was when having Swamp Thing take down corporate stooges in the name of "the Green".
And of course there's a TON of deconstruction happening for many decades. I've been holding back from pointing out The Dark Knight Returns presenting Superman as exactly what you claim because Batman as libertarian revolutionary isn't exactly an example of progressivism, but "Bats goes fash" isn't a one-off. At one point he destroyed the world by giving in to global surveillance.
Oh, and Wonder Woman killed the head of a US spy agency just after that. On live TV. Nerds are still arguing about that one. Also about that time the Amazons invaded the US because they were torturing Wonder Woman as a terrorist. I'm not sure I count that one, though, because they copped out with "the bad guy orchestrated everything" eventually.
Seriously, I promise, comics are weird and have been going for a long time. Writers are gonna write all sorts of stuff. I know it's reassuring to boil it down to archetypal stuff, but yeah, no, people have been messing with these characters for the better part of a century from every angle.