he makes up a significant part of the current core team, and seems to default to hostilities any time the subject is breached.

Yea I was rather surprised by this myself. I somehow came across a thread of his where he was outright rage "I told you so" criticising AP/Fedi over the lack of interoperability between lemmy and masto. And while I'm quite sympathetic to the critique in general, it was rather telling, I thought, to see him spend so much energy describing all the "bad things" of a protocol/ecosystem he's not developing on.