I get the same thing often. I always run all my characters through every area they are able to go to, starting zones included, so by the time I get to the "common" areas all most all of the quests are either green or grey for their levels. I have one character who is currently level 78 and is still finishing up some of the Outland quests.
I like to think ahead of all the gold I'm gonna get instead of the xp on max level capped questing in Northrend.
I just play away and don't let those people get to me. After all as has been said, I pays my money so I play the way I want to not how someone else thinks I should.