Your premise that evolution is somehow a liberal principle is simply wrong. It’s a scientific conclusion which liberals or conservatives can either accept or reject.
This site has pretty much run off all the conservatives who accept evolution, but that is more of a reflection of the religious wing of conservatism rejecting science than proof of evolution having any sort of political bias at all.
I'm not certain how outnumbered we really are. I suspect it's more the case that most reasonable people don't want to argue with idiots, because reasonable observers can soon become confused about who is which. ;-)