Wasn't this game formatted at one point to spawn players in a game in a manner as to keep all the sides even? I seem to recall that as one of the upgrades that lots of folks complained about.
Anyway, Outlaw I personally find it bad form to switch from a team with less players to one with more. Even if you have issues with one of the players you should, like you mentioned, keep that in the forum or chat and just play the game at hand. I watched several folks switch yesterday, but have no idea why they bounced from allied to German, but there you go.
There are also instances where I have fought tooth and nail for 10 minutes or so only to have the reds all leave the game, or all but one leave the game. So to anyone spawning in brand new it would appear it is 4 v 1, or 5 v 1, or whatever, but in reality it was a hard fought game to that point. I find it difficult to leave a side I have so much time invested in because the game is suddenly lopsided in my favor through no fault of my own or that of my team. In that case I will not fire on the outnumbered red and just try to finish the mission and hope the next game is more even.
Regardless of how you play it I think there will always be lopsided games unless zup brings back the alternating spawning in, which drew some pretty harsh criticism at the time.
I think the lesson here is no matter what you do, someone will be unhappy with the result. Don't take it personal and move on to the next game.