It is a valid stance, I guess! I don't agree that it's my job to go out of my way to teach strangers how to play the game, but I don't think I've ever given someone a hard time about being new or having to modify our tactics to suit someone who wasn't quite as geared or whatever. On the other hand, if 4/5ths of the group are geared & capable enough to handle the dungeon regardless of what the fifth member does, I'd rather just carry them through than draw the dungeon out.
But, and here's the distinction, I didn't call anyone an asshole for choosing to use CC. :p