Unfortunately I think that's why she's as popular as she is for most people. Same with Camilla.
Like I don't hate either as characters on their own. Tharja has a softer side to her that you see in her supports with Nowi, Kellam, Libra and Noire that's endearing but she's got more negative aspects than good. i.e. threatening to curse people, her stalking and obsession with the avatar, and what future her does to Noire.
Having these aspects doesn't make her a bad character, but it's why I couldn't support her.