Because it leads to stuff like Tenna's dialogue if you actually attack him.

Because if you do the fight the normal way, it's just, y'know, you're playing all these whacky minigames to try and do Tenna's goofy 1000 points goal.

But if you just attack him, the fight is Tenna realizing
1) He does not have the horses to win this one.
2) Oh, he actually really pissed these guys off for real.

oooh... I should try it lol

I did attack him at first because I thought the point goal was ridiculous, but i didn't stick with it

If you do attack him the game starts throwing gobs of points at you, to the point where his below 16% health line is actually impossible to see in game.

oh interesting lol

so you aren't allowed to kill your tv