Sorta, kinda. To be absolutely clear, he published a full on anarchist manifesto under a DC label, as well as Watchmen itself, which ended up being the ultimate deconstructionist take on superheroes (and does start from a heroes-as-keepers-of-the-system take, but goes way past that eventually).

And, again, it's not like he was pretending to be a conservative while he was doing superheroes.

Again, writers are writers. They write. It's not like there's a sign on the Marvel and DC bullpens saying "status quo defense only". Again, except for that chunk of time where the US government literally did that. But that's a different story, and there was a ton of cultural and countercultural pushback before, during and after.