By labelling someone as a "noob," you're basically debasing them as far as a respecting manner. Just because somebody new doesn't know how the roleplays work, might be younger, and they're character is slightly more glitter-filled than yours does not mean you can call them names, hence labelling them, "noob."
I've seen a close group of buddies or two call each other noobs, but it's just in a joking manner. They're not really into it to be mean or offensive, they're just playing around. I suppose it's easier to call each other a "noob" than saying, "you're a newbie."
Personally, I've never become friends with anyone who uses the term, "noob," because I find it disrespecting and it shows more about the person calling the victim the name than it does the victim being labelled as a "noob."
When I see people name-calling, they're either goofing around with their friends, or they're (not necessarily intentionally) hurting someone feelings. I think especially for some of the younger players, they don't understand (maybe I'm wrong. I've had a few experiences with this, and the victims had no idea what they did wrong) why they're a being called a "noob," and they certainly wouldn't understand why the name-caller is better than them. Why? Because they're not. But it appears to me that when someone calls someone else a "noob," it emits the impression that the name-caller thinks they're better, more educated, higher-ranking, ect, ect...
It's possible people just think that by calling someone a "noob," it makes it easier to label them. "Noob" could mean a sparkledog/glittercat (colorful), illiterate, ignorant, newbie who lacks experience and is easily taken advantage of, all in one person. Some people seem to think it's easier to give them a "fitting title" than to just call them a newbie. But this is just personal experience, so maybe I'm wrong. Hey, I can't speak for all name-callers.
Anyways, I think it's disrespectful and rude. No one should be name-called. Of course, there's not much we can do about it because it's the Internet. But to answer your question/opinion, No, I don't think anyone should be called a "noob."