Don’t federate with that instance if you don’t like its views.
TBH, I find even this view kind of... foreign? It makes sense to defederate from instances that cause harm to the ecosystem (whether by hosting trolls or not guarding against spam) but I just don't think that "federation" should indicate "approval" in the way so many folk clearly do. Like, letting someone on gmail email me doesn't mean I approve of what google does.
I view lemmygrad.ml as political spam and bad thoughts not worth propagating. lib.lgbt is also unfederated from sh.itjustwor.ks because they hosted a The_Donald community while wringing their hands about the free speech implications of jettisoning it.
You using gmail means you approve of what Google does. If Google started platforming alt-right content and you were fine with that, that does say something about your approval as well.