If someone doesn't recognize it as relatively harmless banter (which may be a matter of opinion anyway), then why would they not think it's inappropriate here, when this forum is known for being more civil than most, partly for the reason rituch gave?
The "default" should be to recognize that misunderstandings happen online, and to definitely not post a rude, redundant comment like "get real" to an already heavily downvoted post that two other people have already addressed.
Edit: Well, judging by the down and upvoting, it seems I'm in a minority, or a lot of 'free speech' warriors here don't understand the concept of private forums with rules, and think posts simply telling people to "get real" add to a discussion.