It was only a "mass exodus" in the minds of Carl Benjamin fans. In reality he was a notable individual but ultimately a drop in the bucket relative to all the other activity on Patreon.
I've been a follower of/contributor to some people in that sphere (though not Benjamin, to be clear), but I can understand Patreon making that choice and preferring to be a platform for creatives like musicians, filmmakers, writers, artists, etc.