She's from Earth and hates it because she's faced discrimination for being from there all her life, though. I mean every other Jasper from the Earth batch was deemed defective and shut into the PD memorial space zoo, just because YD felt that Earth is shit and everything made out of Earth soil is also traitorous, defective shit and should be destroyed.
Jasper, however, was perfect, so they let her go into regular service, but she's had to fight all her life to prove that she's good enough. She says it:>Earth is a prison, I got out because I'm better than this place
which, contrasted with the knowledge that every other Earth-made Jasper is locked into the zoo station is pretty damn clear. Also>I've been I've been fighting from the second I broke free of the Earth's crust, because of what YOU did to my colony! Because of what YOU did to my planet! Because of what YOU did to my Diamond!
Indicating that she has to be perfect and keep being perfect and fight and prove herself over and over and over again, because Rose's betrayal tainted everything about Earth and gems coming from Earth.
However, she still considers PD, not YD, her diamond, and still refers to Earth as her planet. Her hatred for Earth is mainly internalized self-loathing, which Steven will proably cure by showing her that Earth has value, things made on Earth have value, and thus Jasper has value even though she's not 10000% perfect all the time, and also HW is wrong. You'll see, he'll sing a song about Earth and friendship, she'll cry, he'll cry, tada