The instance seems to be mostly right wing trolls. I know defederating is unpopular but I don't think much is to be lost in this case and it can save the mods some headaches.
Edit: the response on exploding-heads.com to my reporting of transphobia. Courtesy of the "second in command"
How do you block them? Not a feature on kbin yet as far as I know.
If you'd like to block them here on kbin, go to to their domain page:
https://kbin.social/d/exploding-heads.com
and then click the "cancel" circle/crossout button over in the sidebar next to "subscribe". That'll block the entire domain.