I think that the problem is that it uses informal language making it feel unprofessional. Remember that informal language is used when you want to be casual, in a conversation with friends or family members. It has a personal tone.
Here, formal language must be used as it serves to academic or professional purposes. It doesn't use colloquialisms, contractions, or first person pronouns. Formal language tries to used specialized words that give the text it a tidy and neat appeareance.
A way to rewrite this sentece could be:
Numerous Liberty students have preference for going to Pop's (has contraction because it is a proper noun) because they think it is a nice place.
