THIS PART IS EXTREMELY UNFUNNY.

If you really want to know, I suspect it has to do with the decision to expel Thomas Beale from the SFWA after he called Black people in general and NK Jemison in particular uncivilized and not fully human.

Here is a timeline of events that starts with blah blah women can't do sci fi oh it's all in fun when we mock them. Jemison gave a GoH speech in Australia basically calling out the racism in the genre, Theodore Beale said what he said and then used an official communication channel of the SFWA to make sure as many people as possible saw it, Amal El-Mohtar called for Beale's expulsion, there were a bunch of leaked discussions on a private message board where mostly dudes and all white people said "omg back in my day sexual harassment was okay and we liked it", the SFWA expelled Beale, and... some other stuff, I got lost in the middle. Jemisin's post here is good too.

Scalzi was pretty up front about wanting Beale gone, and celebrated when it was agreed.

I... yeah. It's been pretty terrible.