Mostly people who were understandably pissed off that along with wiping out his blogs, twitter, etc., he took down his github and abandoned his projects without helping to oversee a transition of stewardship. This included a few high-profile rubyists.

And then presumably also some people who always thought his whimsy was a detriment to the ruby community (by making it seem less professional or something).

(Not my opinions, just information)

Are there a substantial number of "haters" who have stated that Ruby is better with _why gone? It seems like a straw man.

It's not a large number of people, but rather some who hold a lot of influence and sway who've attacked _why.

Which people are those?

It doesn't matter. Less attention they get the better.

Like who? Any links?

I'd probably include the people who were trying to figure out his real life identity.

Your standard contrarians, I guess.