If I recall correctly, the only things that don't match my vote were the fight scene and the summons lol.
Almost everything is about Naruto. Are NB members really that "mainstream"?
I don't think it's that simple. First off, Naruto's the main, so that probably explains why he's the most popular.
NaruHina is an extremely popular parring period (check the poll in the pairing thread.) so that winning was a no-brainer and Hinata was to be expected as well.
Madara's awesome, so of course he was voted as the favorite villain.
ransenshuriken is an incredibly awesome jutsu if you think about it. It looks awesome, is complex, and is powerful.
Toad summons would clearly win in the favorite summons category since they're the only ones that can use ninjutsu. All the snakes and other summons can do is just physically attack, while Toads can use ninjutsu and weapons.
As for Minato. I dunno, I just like him and apparently others do as well.
Hidden leaf was also likely since pretty much all of the significant characters come from there.
Naruto VS Pain, no matter how you look at it, was one of the best fights the series has ever seen. TBH, I think I'm in the minority that likes the Juubito fight the best.