Everybody has a slightly different reason for supporting someone, because everybody's situation is unique. If I believe everybody who support someone just wants to ruin America, I'm probably missing a million other possible reasons.
What Catherine is indirectly saying is that she is a psychic and believes she knows everyone's intentions that has a certain opinon. Maybe she is psychic, but the probabilities are pretty low. If she's not psychic, why would she have such strong opinions? Probably because we are in a highly polarized political situation.
I believe Catherine might be suffering from Trump derangement syndrome, where everything related to Trump MUST be bad. There are other types of derangement syndromes too. No matter which side we are on, we must not pretend we know everything about the people we hate, because we don't.
EDIT: I want to clarify that I actually do not know what is Catherine's reason for saying that, because I am not Catherine and I cannot read her mind. I'm just making an educated guess. By no means do I insist I am psychic.