We may have no idea why another feels this way, as we have not given them reason to have such repugnance towards us. No matter whether they try to hide their feelings or not, an Empath can sense their loathing and it does not feel good!
Someone taking a dislike to another is a completely normal and acceptable part of life. We are all different and there will always be some people we do not get along with, whether Sensitive or not.
What is often baffling to the Empath is why some people act in an animostic way towards them, when they know they are a likeable and trustworthy person.