You also have to be mindful of the entire anime vs. manga problem. If the anime were cut and clean, it would catch up too quickly with the manga, meaning an entire story arc would have to be devoted to filler. This is what killed Rurouni Kenshin -- the filler arc meant to give the artist time to continue the manga sucked so bad it killed the show.

I enjoy having the extra stuff that appears in the anime; it's like listening to a longer remix of a song. The crappy flashbacks make the fight sequences sweeter, and the excellent flashbacks, such as the ones of this episode (Naruto's dark hell was amazingly good), are crucial to good character development.