It's more that success attracts attention, some fraction of attention will always be negative, and the haters tend to scream louder than the likers. I'm still a loyal GMail user, I still visit Reddit frequently, and (despite some quibbles and a rejection) I generally think YCombinator's done a lot of good for the startup community. But you don't hear from folks like me often: we're happy, the software does what we want it to, so we have little reason to speak up. Folks with a gripe, however, are willing to put countless hours into venting their spleen.
That was one of the reasons I left FictionAlley (a non-profit Harry Potter fanfiction archive). 99% of users were very appreciative of what we did. However, 1% were not, and the 1% took up about 80% of our time and attention. When you're not being paid for your work (FA was all-volunteer), 80% is far too much time to spend on people with massive entitlement complexes.
(There's perhaps a lesson for prospective founders here: build anything worth visiting, and people will hate you for it. Not a lot, and not nearly as many as it seems, but you better be prepared for it and willing to put it in perspective.)
The latest fad in business now seems to be "fire your customers" - get rid of the 1% that soaks up 80% of your attention, so you can better serve the 99% that actually appreciate what you do. I dunno if that's applicable to YC; probably not, since they "fire" 95% of their customers simply through lack of resources and the haters come from the people who're not doing business with them anyways. Ironic, that is...
This was certainly the experience at Google. I don't think that there is necessarily a solution, though it helps to avoid things that could be misinterpreted, even though that also means avoiding some aspects of the truth unfortunately.