OK, care to explain why?
Forcing Balanced Teams ensures that new players joining the server must join the team with fewest players, so the teams are even in terms of numbers if nothing else. If this were not so, players could join either team and would probably do so based on preference (i.e. they prefer playing Axis or Allies or they prefer playing a certain Class and one team offers them the opportunity to do so where the other doesn’t, even if it means they’ll be joining the team with the most players).
You then end up with unbalanced teams, which is no fun for anyone.
One alternative is to enable Shuffle Team voting, which rarely works as the superior team (which without forced team balancing would probably also be the team with the most players) will almost never consent to being shuffled.
Another is to have an Admin present to force team shuffling, but this is not always the case.
Either way the problem with shuffling is that, even if a vote succeeds, or is forced by an Admin, players can always switch teams if they don’t agree with being shuffled.