Could it have something to do with their post announcing intent to federate trying to both-sides the Russian invasion of Ukraine? www.hexbear.net/post/280770 (not even getting into the comments there).
I don’t see how that’s relevant to the hexbear defederation. Lemmygrad takes a stronger stance on the SMO in general, we’re still federated.
Personally I’d be cool with defederation from lemmygrad too, for the same reason.