Just because someone holds back their rescourses doesn't mean they don't qualify, otherwise we should remove Light Yagami from here. Starlight's worst act was an accident, Nightmare Moon's goal has no hints of being deadly (in an alternate timeline it's shown that everything is fine outside of there being an eclipse), and Cozy, Crystalis, and Tirek's goal seems more on conquering Equestria and not destroying it. Meanwhile, Sombra enslaved an entire kingdom, psychologicaly tortured the Crystal Empire twice, threatned Cadance's and Shinning Armor's infant child, and then psychologicaly tortured everyone in Ponyvile simply to spite the Mane Six. And if you say that there is no indication those are true, we see when the Mane Six are briefly brainwashed that they are put in their worst nightmares.
