I think he'd been triggered by Oancitizen for a while at that point, since he made it sound like he never really liked the name, and he always referred to himself by his real name in his videos. Unless you're talking about like a specific incident when he flipped shit, in which case, I know nothing.
(edit: just saw your edit, lmao, now i feel redundant)
Speaking of "Oancitizen", does anyone remember how Kyle responded to the "Ralph Oancitizen" and "Escargoancitizen" fan nicknames? Because that seems like the kind of thing that would've bothered him, but I can't recall if he ever spoke out.
Honestly, depending on your interest level in arthouse cinema, Shakespeare, film technique, etc., his videos are informative and well-made, though a bit dry. But they require an absurdly-high tolerance level for SJWisms and pretentiousness which can be alienating if you don't buy into all that.