I've been a waiter or bartender on and off since University days - I'm really sorry you've experienced that. Making someone feel unwelcome is maybe the worse mistake you can make as a Server in restaurant - it leaves an impression on people, as You've noticed.

Obviously, they failed their job responsibilities - failed at being people too. The owner/manager should never be allowing such behavior, if they are acting in a way that makes you feel like you do, that shouldn't be happening at all. That is an administrative failure too.

I'm sorry that it's like that. I'd say stop eating there but you shouldn't have to do that even.