Exodus has been leading a Brotherhood cover band for most of his career. The poor guy puts together a totally sweet MagnetoCon, but the old man is like "Yeah, no, I'm not evil anymore and sucking up to sellouts is a better career move right now. Peace out, yo". Fast forward to Exodus thrash-talking the Pretender, whom he probably blames for Magneto's descent into not being the awesomest ever anymore. You just know he'd pretty much cackle at Magneto being humiliated "for his own good", but freak the efff out if the old man got fed to Krakoa.
So.... yeah. Magneto fanboy sounds just about right imo.
The real issue should be mutant youth's feelings on the matter. Enrollment at the "Bishop Academy" (I forget the name) was so low they didn't even bother with a first semester. The kids are still clearly salty about the dude unleashing a bunch of Sentinels on their home. Can't help but wonder how Magik somehow(?) didn't pick up on that.
That happened after Messiah Complex/War, though. The possession storyline didn't really absolve Bishop of anything.