Another one who didn't read the manga but just followed the waves I guess.
Here is literaly obito himself telling kakashi that rin isn't the only reason he is doing what he did lol.
It's important to understand that Obito wad still 12 or 14 when rin die, Rin was the closest thing to him for family. And this right after obito himself suffered severe wound with his idea was shaken and madara already planted seed of doubt in his heart about the world and Tsukuyomi.
Rin was kind to obito, a teammate, never mocked his idea and obito truly cared for her, its not simply some crush) someone like that prematurely meeting her end because some grow ups who represent each great villages couldn't keep their bloodlusts in check and started a world war forcing children to participate despide being not prepared for it.
If rin lived she would end with kakashi while obito would have moved on.
Obitos hate is directed at that system and he want to abolish it.
And since kiri was the ultimate actor in rins dead beside konoha (who send rin and kakashi again to their dead after they survived the iwa front) rest is history.
Obito Lay waste in kiri turning their kage into a puppet and started a bloody Civil War enjoying his revenge.
As for konoha there is the Uchiha massacre and nine tails attack.