Some people think that just because they have some money to offer, they are entitled to be rude to others.
I said “some people”? No, no… In fact, there are MANY people like that.
What amazes me is the fact that, even when they have a choice, several freelancers will still beg for an opportunity to work for those aforementioned rude people. Come on! If someone mistreats you, why should you still want to work for him/her? Of course, if you were nearly starving — and I mean it in the real sense of the word –, then it’d be acceptable (although morally painful), because in this case you’d be desperate. But when all you want is to earn some extra bucks and/or more experience and credentials, and assuming that you know where to find new freelance opportunities, you should definitely not make business with unkind types.
Do not humiliate yourself. If you know that you tried to be nice and professional, and still all you got was a harsh response, just ignore it and go look for something else. And if you see someone mistreating other freelancers, I’d advise you not to make business with this person either — you may be the next mistreated one.