WHAT?
Let's take this piece by piece.
There are two different ways people enjoy this game. One way is by trying to win.
K gg no re, in the first line I've won. Even you admit that you have fun, not by winning, not by achieving victory, but by trying to win, by
striving for victory. So its completely reasonable to expect both teams to enjoy the game. Just the same as even the loser in a brilliant chess game can appreciate the beauty of the winning combination.
The other way is by vetting up units. If you win against me, you may very well have ruined my fun (although mind you losing can still be fun, in some situations). If I vethunt against you, I may very well have ruined your fun. Yay, doublestandards?
I don't think anyone solely derives pleasure from vetting up their units. Regardless, there's no double standard; if I don't strive for victory as well, then your achievement of victory is meaningless and so you won't enjoy it either. My point is that I won't beat you for the sake of ruining your fun, but for the sake of actualizing my own fun.
In addition, all competitive videogames are some sort of war. You are fighting each other with the most common goal being to win. Making the opponent frustrated enhances your chances of completing the goal.
First of all, competitive video games are definitely not a war, they're a competition, a struggle. (certamen)
But, frustrated your enemies for the sake of victory costs the END GOAL of the activity (if only to your opponent). I mean, if your sadistic, and the only way you derive pleasure is from pissing off other people, then I suppose you may have a point. Winning isn't an end in itself, though I suppose competition might be. (Aristotle's virtue ethics?)
In fact, frustrating your opponent's probably destroys any hope of good competition in a game. I'd imagine winning is significantly less fun if you know that you are only winning because your opponent is pissed off and making stupid mistakes.
On a larger scale (playing to win on a community level) though, its probably to your advantage to not be an asshole just so better players will be willing to play with you and so when you win, your opponents don't drophack ect. Also, I guarantee you'll have more fun/more friends in the community if you're not an asshole.
If you don't like this, go play co-op games, or just singleplayer games. The entire premise of competitive gaming means that sometimes, one party just isn't going to have tons of fun.
Assholes like you are pretty much the reason I don't really play competitive multiplayer games very often anymore.