There is a very fine line between being an “evil” spawncamper and someone just playing a good game.
I think spawncamping came from earlier FPS’s that didn’t give spawners invincibility. These games were all about getting the most kills so spawncamping became a “good” tactic on gaining many easy kills. It became “honorable” to allow your opponent to run and get ready by getting body armor, guns, and ammo before comming and fighting you. As a side note that could start it’s own thread: why is this so honorable? Aren’t those games about kills?
ET isn’t about getting kills (much to some peoples surprise i’ll bet
), it is , IMO, a realistic warfare simulator, not just a FPS. Since I look at it as a “simulator” I consider a match a battle. Do you think that the Allies asked the Axis “Please don’t shell the beach” at Utah? Please.
There are some questionable game play practices though. Hiding in a spawn, swimming in the water on the beach (but, go ahead, i need a new pair of pants
), etc… But, shelling the spawn exit is part of the game.
If you dont like that kind of warfare, you should play the new revolutionary war mod where you all stand in a line and shoot at eachother. 
–funkPig
Keep after it and keep moving it. Allies will follow it, and the rest of your team, or the next spawn wave might get a chance to be shooting at their backs.