I think part of the reason for the Y Combinator hate is that the valuations YC offers are so low and it's not clear whether YC significantly helps the teams it funds. Wait, don't throw those tomatoes, let me explain! The valuation YC offers -- a median of 250k for a two-person team -- would be absurdly high if it was being offered to any team of two recent college graduates; but YC doesn't make offers to just any tea…
The startups offered YC-funding, who declined it... how did those guys work out, in comparison? (although the offer itself is an important YC input).
Also, the YC guide says they they decline funding to many very good applicants (because YC has limited places and they go to the very very good applicants). It sounds like these guys would have been selected, in some other batch... YC knows who the "almost selected" guys were and could do a comparison.