I've seen at least in two YC videos a very clear mention that the recommendations don't have much weight, basically saying "don't worry about it".
Secondly, is YC even that homogenous? It may be skewed towards enterprise software, but they do invest in a far wider range of startups than any other VC. And the ethnical and gender diversity is not that bad either, all things considered.
Which is probably why YC is so homogenous.