Man it is so weird watching people sling this much hate just because a character isn't baseline shounen hetero love interest FC.
Especially the dudes that are all, "She turned him down? She deserves to be alone and miserable just like the girl from high school I liked but wasn't interested in me that I still stalk on facebook five years after graduation!"
Seriously, you're telling on yourselves something hardcore.
First of all, that is a strawman argument.
Second of all, a character can be more than a "shounen hetero love interest FC", however, Chita is neither this nor anything more. She's a 2D flawed character that does not try to improve herself in any sense of the word. And don't get me wrong, it's fine to write a flawed character, however the audience expectations are that such character will eventually either grow as a person or meet an end adequate to their lack of effort.
So now look at Chita's arc. She starts flawed, yet she does not grow, her situation does not change, the world around her also does not change. Her arc is "this meeting should've been an email" of manga. A waste of time spent on an impersonification of negative traits.
This is where the hate comes from. And not out of some twisted goonerism like you'd paint it to be.