I don’t think software should be expected to take a political standpoint. It’s not something the Discourse developers can feasibly enforce either. There’s no way they could take everyone who breaks their ToS to court.
Hosting companies on the other hand can and should take a political stand, and they frequently do. They’re in a place to effectively enforce their rules. And with your community’s own ToS and overall culture layered on top of that, you can easily decide what goes and what doesn’t.
We can’t take their freedom of speech (in their own communities) away, but we can be much, much louder than they are.