You have every right to be pissed off about it but a photographer or artist (or anybody else), legally speaking, (in the U.S. anyway, if I understand the law correctly which I'm not promising...and I think the laws are similar elsewhere) has every right to take your picture or draw your likeness AND even make a profit from it without your permission. However, they cannot use your image to promote a particular business or product without your permission. But yeah, it would be polite to ask your permission first and to respect your wishes. Also, I have no idea what the laws are on this elsewhere but my understanding it is the artist who owns the art, not the subject of the art so an artist can make a likeness from you or a photo but can't steal your photo.
From your description, it sounds like he probably didn't have any intention to be discourteous and had no intention of offending you (at least initially). You got upset then he got upset because you got upset. People tend to do that, especially if they feel they haven't really done anything wrong. I am giving him a little bit of the benefit of the doubt but just thinking that if I were an artist (I'm not...not even close) that I wouldn't give a second thought to making a drawing from a publicly available photo. Invading someone's privacy wouldn't occur to me because it's already public. Just another example of how assumptions can get you in trouble and I'm probably making plenty in this comment.
You can express yourself however you like because like you said, interwebs... But courtesy works both ways. He may have been discourteous from your point of view but was it intentional? Would it have hurt to explain your point and ask nicely? I get the impression that you were probably rather direct (or at least the other person interpreted it that way) but I could be wrong not having seen the conversation.
Again, obviously you are under no obligation to be "nice" or anything. But at the end of the day, if he feels like it, he can distribute his artwork of your likeness all across the internet and sell prints or whatever. Being nice about it, even if he is the one that screwed up, is more likely to get you want you want.