Empathy is an ability to understand how other people feel, without having to agree with anything they say.
In order to develop empathy, drop the idea that you must agree with people. Tell yourself, “If I believed what they believed, then I too might feel that way”.
Example: If the person feels they have not received fair treatment, (whether they have or not is a different question), then they would feel annoyed.
The unempathetic person usually lacks empathy because they think: “I disagree with you, because you are obviously wrong, stupid or dishonest”. With that thought process, empathy is impossible.
Empathy is built upon temporarily accepting the other persons point of view and feeling the way they feel.