It's sexist that Cass can't just have those feelings of obsession (like Tim) but instead has to have hers openly sexualized.
I'm probably stepping in it here, but I would argue that it's not so much sexualized as it is physicalized. Anything we see her doing is best compared to someone with Asperger syndrome hearing the words but not understanding the tone. We can see what she does, but the core of her character's origin states, we're tone-blind to the subtleties of it.
If this was Babs or Steph in that position, I'd agree with you, but given the nature of Cass's upbringing and talent, I think there's room to assume a chunk of her motivations are unknown and alien to us.