According to the list of badges there is a per-site requirement that each of the top 40 tags needs 200 questions, before Generalist badges are given out.
According to this comment on CodeReview.SE's meta, that is no longer true, because they got those badges before reaching this limit.
Looking at their Generalist timeline it looks like either the limit was removed on 5 May, or the limit is now lower (and that lower limit was crossed on 5 May).
So what is going on here? Does CR have a different limit than other SE sites? Do Betas have a different limit in general? (If so, what's that limit?) Or did the restriction change across the network?
At least, I believe it didn't vanish across the network, otherwise CodeGolf.SE would have at least 3 Generalists, but so far none of those have been given out.