I dont know how to put it, but whatever id say i doubt you understand it, because it should have happened already.
Im not saying that you are stupid...but i fail to see how its not an easy concept to understand?
If i camp a soldier, i will prevent him from getting up right?
If that soldier cant get up, he cant go do his objetives (get exp, items, socialize...whatever).
If a soldier cant do his objectives and become stronger, it weakens the other side.
If i weaken the other side, i will have better chances of winning the war.
Preventing the other faction from doing their objective, is my objective as a simple soldier running around in Azeroth.
So by preventing him of doing his objectives, i fullfill my own objective.
Dont play war if you cant handle war - there are (like i said) other games you can choose to play that dont have this theme.
I dont know how to explain it further, because its just logic.
Now, you might feel offended and probably resort to anger and refusal to accept, but just try to take a deep breath and try to understand.
Either way, i will be expecting your response.