I think that the MC is written to be a jerk and that most of the other vault residents are just tried of that behavior and react with the same energy the MC gives to them , This is best shown in the first sex scene with Mary where the MC says "Usually girls swarm around me to get a taste of my divine cock, and you suggest giving this valuable thing up just for a simple head?" Of course most of the MC's peers would dislike them, they're an Asshole!