Honestly, it's no use. The main reason why people refuse to look further is because they're disappointed with Kishi's choice. It's a common fact that when a person disagrees, they become unreasonable... even narrow-minded.
Personally, it's clear what Obito stands for and what he wishes to accomplish (this battle is the repeat of the younger brother (Naruto) vs older brother (Obito)), but I also wish there was more to Obito's flashbacks. We knew Rin's death was going to play a huge role, but it turned out to be the only event that changed him completely. Tobi himself is such a dynamic character, so I guess people expected to find out a list of twisted and sinister stuff, especially with Madara involved.