It's only rude if the person you're saying it to takes offense. And I mean really dude, you handled this pretty poorly.  
  
http://i.imgur.com/6yIcqSk.png 
http://i.imgur.com/fcn4qDI.png 
http://i.imgur.com/yXpJ3Zo.png 
  
If you're going to have that kind of discourse with a regular user at least do it in a PM. I find the way you acted more out of line than what was actually said.