In the videos that play during the theme songs of iCarly and Victorious, we see lots of clips that haven't been used (examples: the second to last shot of Season 4's theme song, when Carly and Sam are holding shovels and then toss them, the clip with the entire Victorious cast on the balcony of the Asphalt Cafe that shows just before Dan's name is credited, and many of the ones that are used in Freak the Freak Out's unique opening). While some of the clips used were most likely from extra takes, what about the ones that we haven't seen in any episode? Did Dan just shoot them for the sake of new clips?
Unlike iCarly which uses a montage mostly made up of clips from the episodes and the occasional Throw It In moment, Victorious specifically shot an intro separate to the rest of the episodes and only uses a handful of in-episode moments to make up the rest of the intro.
What does Dan have against Northridge? Anyone from the LA area knows that it's not a bad part of town, but Northridge High is the rival school in Zoey 101 and every time they talk about "Northridge girls" or anyone from Northridge in Victorious, it's treated like the scariest, most awful place ever for no reason.
Northridge, CA is in the San Fernando Valley. Valley girls are stereotyped for being shallow, promiscuous, and materialistic, among other things.
After I was adding an example about Nerds in their respective place in Acceptable Targets, I realized, Dan, or at least one or two, if not more, of his writers, seem to absolutely hate the entire concept of being a geek. This isn't like wit other shows, where a nerd being a nerd is the joke. But comedy seems to be built up on presenting a nerd, and then beating the poor guy senseless. Then, they'll depict the nerds as Insufferable Genius types or Cassanova Wannabes, just so they can almost say 'look, its not like they don't deserve the beatings!' I already dislike iCarly a lot because of how it treats Freddy, which takes this to Dude, Not Funny! levels, but most of his other shows I do like, but I can't get past that if there's a nerd, they will almost always be beaten mercilessly, and usually far more than any other character. I can't name a character in his shows who suffer the same level of Amusingnjuries who doesn't have some nerdy credential to him (and its always a him, the only female nerd explicitly shown was given a pass, and making fun of her was treated as a Dude, Not Funny! thing). So, why, exactly, does Dan, or his writing department, hate nerds so badly.
Self-Deprecation? Either that, or Dan's writing team is stuck in a time loop where nerds are still fun to pick fun at.