Well, this is an interesting situation. Personally, if a good friend of mine carried a fake bag, it would bother me because I would never carry one, but not to the point where I'd ever make a big deal out of it because SHE is carrying it. Why... well, because her circumstances may be different (ie the price limit she has for bags may be, I don't know, $500 or less), she may choose to spend her money on other big ticket items (and luxury bags don't enter into the equation), etc. etc. Is that the case with your friend?
If an acquaintance or "friend" of mine said something like "Expensive bags are so worthless and the people who buy them are idiots", well, sour grapes is what comes to mind and I'd be more concerned by my supposed "friend's" lack of respect for me than anything else. I may not like something my friend has, carries, or uses, but I would never be rude or judgmental about it. Sometimes people make comments designed to cover up insecurities and pretend they really don't care when they obviously do. Maybe that's the case... maybe it isn't. I think the bigger question is does your friend respect you and treat you the way a friend should? If so, well, I'd forget about it. There are so many things people disagree on, and this may be 1 of 29382938 things you and your friend disagree on. No big deal, unless there is more to the story. JMHO.