Disrupting existing markets (not a component of all company-building, but certainly a critical piece of many YC companies) is fundamentally about political issues.
I don't want to have to hunt down incubators that donate to the RNC or Libertarian party just to keep my hard work from helping people I strongly disagree with on nearly every issue(DNC.)
This doesn't eliminate opportunities, but creates them -- funding a conservative incubator now becomes a potentially viable business plan.