it's hard to imagine why someone who's a fascist would not understand why people hate fascists. hitler was a fascist. mussolini was a fascist. fascists have historically killed a lot of people for stupid reasons, like, that they were jewish, gypsies, queer, etc.
fascists believe in things that are antithetical to anarchists (a strong leader, nationalism, women being subservient to men, etc). we don't have to hate people who disagree with us theoretically; it is hard, however, not to hate people who want to kill us and our friends, either directly (through street violence, for example) or indirectly (through policies like concentration camps, immigration control, etc).