Earlier today I was playing Bad Company with my friend on the map Arica Harber. We weren't being serious though, just dicking around. 
Normally I'm an objective player, constantly capturing flags and arming/disarming M-COM stations.  
We started out serious, until we realized it was a lost battle and just said "Fuck it". 
 
Well halfway through the battle, around the bridge point (Rush) someone saw in blowing up building having the time of our lives. He then sent us messages saying  "Useless Noobs"... I'm also a level 27 by the way and my friend is a level 21. The antagonist was a level 50, so I'm guessing he likes this game.
 
So am I in the wrong? Should I always be an objective player, or should I be allowed to dick around every now again. 
 I know the answer, but I want to know what you guys think.

I sometimes join games of TF2 just to have some fun, not really going for the objective and generqally just doing what i want to do.

Its only a game. People invest too much into them, winning isnt everything.You were in the right.

There's a bunch of players. No problem with dicking around as long as you're not messing with other people's games.

Yes.
 
I didn't read any of this, but you are wrong.
 
You are a foul human being and deserve any punishment you receive for your vile actions.

Nah some people take things too seriously

If the match is hopelessly lost, I don't see the problem with having fun while it draws to a close.

If it's a done deal then whatever, doesn't seem near as dickish as just dropping out.

who cares you paid how ever much you paid for the game to have fun, how you want.

I personally would be annoyed if I saw people just dicking around but at the end of the day, it's just a game and people should get over it. If that guy felt that what you were doing justified a message then so be it. You are not wrong, he is not wrong. It's a game and you can choose how you want to play it. The guy who sent the message probably should have just been quiet and accepted that two people were goofing around.

Sometimes people can be awfully liberal with sending messages. Once I was playing Black Ops and this guy felt the need to message me "Shit host is shit"... Like sorry my internet connection is not up to your standards.....

You can dick around. Unless dicking around is killing your teammates.

@NewfieBullet said:

You can dick around. Unless dicking around is killing your teammates.

I think anyone who uses the word "noob" is a bad person, so I'm siding with.
Seriously though, it's not up to you to make sure this guy is having a good time. Everyone has their own definition of fun, and it's not like you were being rude (intentionally), or harming anyone (that I know of)