I have two questions here:
1. You say the zsu was empty when you LAW'd it... why would you do this instead of just get in it and move it off the runway? You said you were aware that the zsu was there from a long trip from the enemy main, why would you give it back to them? This action alone could be worth a kick or temp ban. Destroying your team's vehicles.
2. You seem to be upset that you were kicked for chopper camping which you think was based on hearsay, but you are angry that another individual wasn't kicked based on hearsay (even if it was his own). Isn't this just a bit contradictory?
If an admin doesn't see something, he is under no obligation to take action. If someone notifies him of something, it is up to the admin whether he takes action or not based on the situation and who's doing the notifying. Even experienced players are often times unsure of a situation, as you were with the ramming incident. Has happened to me as well.
And one other thing, if Devildog says you TK'd him, then he is the one who's going to be believed. Whether you TK'd him or just blew up the ZSU, he was totally justified in giving you a tempban.
You seem like a decent guy, so just be more careful in the future, and try not to let emotion get the better of you (that's tough for a lot of us
)