Excitable Boy
is a metaphor
In Zinnia's case, she sided with the bad guys, stole plot-relevant stuff and attacked the heroes.
that's still weird, though
what Maxie and the Magmas had going for them, IMO, was that they had genuinely good intentions behind what they were doing (and if Zinnia hadn't been manipulating them, it's totally possible that they would've called off the Primal resurrection when they realized their calculations were astray); their methods were extreme, sure, but the team's camaraderie and commitment to their leader and to their goal portrayed a true sense of staunch devotion to their dreams of aiding humanity, and in the aftermath of the crisis, they're trying to find ways to aid civilians and expiate their actions. When Courtney goes rogue, Tabitha works to help bring her back into their fold, and the apologies between her and Maxie portray them as more of a family than anything else (and all done with significantly less direct lore-shoveling than Zinnia had, spread throughout the game)
contrast Zinnia, who acts like an insane smug jerkass for the first 90% of the Delta Episode and then tries to overcompensate by cramming five minutes of sympathy-appealing into the last 10% of it