Comicsgate is a bunch of nerds complaining about mostly Marvel comics having a bunch of sjw politics and/or becoming performatively woke as of the last idk 6 years (mostly under Axel Alonso iirc). The main players in comicsgate is Ethan Van Sciver (a conservative comic illustrator) and Richard Meyer (an online critic that became a comic creator himself). The main flashpoint at the moment is a court case between Richard Meyer and Mark Waid. tl;dr summary of court case - Richard Meyer decided to make his own comic resembling the era he grew up in comics with (no sjw politics, strong man stuff etc) and got a publisher (Atlantic) to distribute it for him, Mark Waid then used his influence in the industry to get Atlantic to cancel their contract so Meyer (who goes by Diversity&Comics online) sued Mark for interfering with his contracts/business.
I actually know this stuff quite well as the only other boards I read are a comics one and an anime one.
tl;dr - what is comicsgate? dont ask, it's dumb. ignore all this bullshit and live a normal life.