I have to agree with that. Just because you're submissive to your dom doesn't mean complete strangers have any right to be dominant towards you. They're your equal and your dom's equal at the same time, because there are no agreed BDSM dynamics at play when it's random people, or even friends you're just not involved with that way.
It bothers me when people meet a dom and a sub, and think they have the right to disrespect the sub. Shows what kind of people they are, really.