I haven't found that to be the case at all. You ask someone out, they're interested or not, you both continue onwards in the group with no hurt feelings.

I have tons of female friends in social groups whom I've asked out. Some had boyfriends or even husbands and we all had a good laugh about it afterwards.

Where it gets messy is when people start hanging out one on one with members of the opposite sex, calling it "friendship", and then confessing feelings.