The group that hacked the game has every right to put an intro on it in my opinion. They've already released a clean, completely untouched rom. The crack was released separately from the clean release and is entirely optional. if you don't like it, don't apply it to your ROM
As for your rhetoric about P2P sites putting intros on, aside from the fact that most sites and most release groups for that matter wouldn't have the skills to be able to do it anyway, look at it this way - the developers deserve their logo at the start of a game, the shop you bought it from does not.
What I'm talking about in terms of ungrateful is people going "OMG, Xenophobia have released Zelda early. Waaaah, it's got piracy protection, someone crack it, why isn't it cracked yet, when will it be cracked, why can't I play"
Followed by, when it's cracked
"Waaah, it's got an intro on it, I have to press A before I play this $40 game for free before the release date that someone's just spent hours of their spare time removing the AP checks from for me, waaaah"
Just shut up and play it, or even better, remove the checks yourself or update your loader. Yes, it would be nicer if the intro had animation or music, but from my limited understanding of DS architecture it's difficult to access the sound hardware when you're loading code before the game boots.