Following that logic anything can happen because. Which I'm not denying is entirely impossible but tv follows basic rules and a children show making the dead mom who sacrificed herself evil and nobody noticed? Maybe she used to be neutral/chaotic and changed. But nobody noticing, not even Garnette who isn't as crazy about her as the rest?
As to Pearl from a beginning her character had attributes that she had deep issues. It isn't surprising if it happens in that aspect.
As it stands now, anything CAN happen. See, the stories told from Steven's perspective and it always will be. Until it's shown to him it's a mystery and every character here has their own bias and pov on things. It feels like we're always walking in on the middle of a convo with these characters because of this.
Example, Lapis. She's all "You knew I was in there and You kept me in there all this time! I never believed in earth/ I just wanna leave/ lets stay on this miserable planet together!". Seems like she hates the CGs cause they kept her in a mirror among other things. She doesn't like earth and just wants to leave. She doesn't wish for HW to go to earth either so I assume wasn't an enemy before being mirrored.
Thing is, our Gems don't know her. They had no clue "such a powerful gem" was in the mirror and the mere fact that she was in there makes them think she's bad news. So clearly the Crystal Gems were a thing before Garnet and Pearl, maybe Rose did some not-so-good things before they met her and Lapis is one of those things? She leads wars and impresses Jasper, the asshole long lived warrior, with her tactics... she likely did a lot of not soo good things in the past.
We then see that Rose hides things from all of them so even Pearl's worship/ love is based on only what Rose allowed her to see.
Then we have Garnet. Maybe Garnet doesn't gush about her because she knows a tiny bit of the not-so-good parts from the possible futures where Rose fucked up after Garnet became a Gem. And ontop of that FV doesn't tell what Rose is thinking or what she's doing in her alone time unless Garnet finds out about it in some future I guess.
And yes, showing that Rose has either a dark past (very likely imo), impure motives (also likely imo) or extremist idles are both pretty common in cartoons and anime. We still don't know what causes corruption or why so many gems on earth are corrupt, we just know that Rose tried to fix them. Maybe she caused it and was trying to make up for it? Maybe she did it for a not too goody goody reason? Who knows ...