SP always appears quite stern.....
I don't I agree, I've seen several pics of her smiling, but then I worry that's going to be turned into "meanie old bigot smirks as she goes to court to persecute poor little harmless TW".
Also in other pics I'd describe her as looking no-nonsense and experienced, not stern, but but doesn't matter if she looked like Miss Trunchbull. In a witch hunt anything can be turned against her.
Whatever she looks like, she's female and entitled to a female-only CR, and she's legally allowed to not perceive a TW as female.