I mean in terms of "what we think scary child killers look like" there's quite a difference between this picture:
And this picture:
Yeah, one is a social media post and the other is a mugshot. I’m sure Myra Hindley also smiled for a picture at some point in her social life. The difference is only that we haven’t seen it.
The “i didn’t think they would look like this!!??” stuff is absolutely part of the same societal bias that makes missing middle class white kids more newsworthy than poorer or non-white ones, or makes photos of black men killed by the police look sinister by cropping out the context, but then paints a serial killer of babies like… that
How deliberate it all is is debatable, but on a societal level, yeah, it is an issue. The question is do you think a black or Muslim nurse from a similar background would have the same kind of incredulous questions asked? If you do, fine, I personally don’t. At least not nearly to the same extent.
It’s also actually not that weird that she isnt a man, as crimes of opportunity that involve poisoning are much more likely to be done by women than any other type.
As for “why”… isn’t it fairly easy to imagine a power/God complex forming in someone who felt inadequate? Why does her having a stable family life entirely preclude that?