fear can absolutely be that big. i used to send snapchats of my snakes to people until one of my friends told me to stop in a less-than-polite way. an unexpected picture of a snake caused him to get mad at me! idk if it was a phobia or ignorance, but one can be helped while the other cannot.
when i'm scared of something, i try and learn all that i can so i can better understand myself and the source to either prove my fears correct or just learn something new.
there's a difference between a phobia and a fear derived from willful ignorance. she's purposefully choosing ignorance over hanging out with you at your place.
honestly there's the possibility she doesn't even understand how much her behavior affects you. people get so wrapped up in their own minds and beliefs they have a hard time understanding how others can feel differently, or how their attitudes about those things affect others.
she sounds willfully ignorant.