[@Archmage MC]

there's kind of a wide selection reasons for the rebellion that are personal to those who join.

[hider=probably spoilers]
love the earth (Rose)
rejected by home-world (Garnet/Lapis)
hate the diamonds and their cast system (Bismuth)
went along with someones else's rebellion because they matter more to you than homeworld(Pearl)
I live here(amythest)
and finally you have peridot who is basically a combination of all of the above
[/hider]

pick one or make your own, there's no real specific binding philosophy on why/how much they're mad at home-world, so long as your consistent with why/how angry she is. 

on a side note, I am aiming to post today.