How to respond to something this RUDE?

Don't let the kids get involved. If they are friends, they should still play together. However, in the future I would try to only deal with Ashley's dad. If he (or she, for that matter) asks why you're not talking to Gloria, calmly explain that you have no interest in dealing with someone who's going to be so close-minded. If it ends up that you're not friends with them anymore, maybe it's better that way.