Because many people hate what they don't understand.
Others hate what they can't control.

IME, cat haters dislike cats because they don't "do as they're
told",
"are sneaky", or other inherent characteristics of cats that
disagree
with the person's perceived superiority over life in general.

--
~kaeli~

and they're also mysterious and sometimes you can't tell what they
are thinking.
Alison