Yeah, even the praise might be in this slightly condescending "well, I must say you are surprisingly competent - despite your origins" kind of way.
It also explains how at first she was boasting so much about how "fighting IS her life", or about how "Earth ruins everything it touches, except her" but then in "Earthlings" sounded really bitter about having had to fight every second since she broke through Earth's crust because of what Rose did to her colony, planet, and diamond.
Because of Rose, there's this huge stigma on all Earth-made gems, and she'd had to fight every second to prove herself and overcome it and earn a right to stay in service. She's probably gotten sent to some pretty bad missions, too, because HW would rather sacrifice one of the gems with the twisted, traitorous Earth soil at their core than one from a good batch. Everyone only gets what they deserve, and she's fought damn hard to deserve the right to be treated like a regular gem. Until she failed and Earth tainted her, too. Maybe she always thought it would, maybe she always feared the shit Earth soil she was made of would one day manifest and she'd turn out flawed and worthless just like the rest of her kind.
I honestly think that when Steven uses friendship-fu on her and gets her to see that Earth does, actually, have exceptional, unique beauty and value, and that finally she doesn't need to be ashamed of who she is and where she comes from, doesn't need to be PERFECT every time in order to be allowed to exist, she'll mellow out amazingly and will turn out to be a lot more like Amy or the rest of the Famethyst at the zoo.