Just lost 6 customers terrible service over 1 doll...

Just lost 6 customers terrible service over 1 dollar. Two friends came back on leave from the coast guard so we went out for a good time & we left with a bartender going out of her way to make us feel bad about not tipping yet on
2 draft beers saying "we don't serve people who don't tip". Which a 20% tip would of been a dollar. We are good patrons who tip well normally wasn't expecting a rush to do so. Very unprofessional conduct by the bartender and technically against the law.