It's pretty simple: the game should be allowed to run its course unless both players (or the tournament rules) agree to the contrary. So if one player doesn't want to allow rage quit, for whatever capricious reasons, then that's that. So Yakal doesn't really need to explain anything; if he doesn't like it, he doesn't like it.
I'll offer some ideas for why it might be the case - though, as I say, these don't have to be convincing. For starters, not everyone is playing just to get better. They might actually enjoy the whole match process: the startup introduction as characters join the stage, and the closing screen. Maybe they love to hear ganondorf laugh, or to see how many whiffed grabs they had. Considering that, given the "normal" course of the match,the player will see this, the other player is preventing or interfering in his ability to do this if he rage quits.
As for the taunting, that is arguably part of the match. It is a move given to the every single character as part of their design. Clearly, it is dangerous to taunt, so if used at all it may have to be tactical. But in this sense it is "natural" and not superimposed.
So yeah, imo if even one person doesn't want the rage quit, it shouldn't be allowed for that match.