Dehumanization is a core mechanism of fascism. It’s not possible to eradicate fascism by using its tools. Your statement also stands in stark contrast with your position that empathy is the most important part of a person.

The problem is, we’re all capable of atrocities, even if some are much more easily convinced to participate than others. It’s an uncomfortable truth of being human. But we have the choice to attack the parts which are actually contemptible - their words and actions. Alienating people based on their physical appearance equally alienates the people who perceive themselves to have a physical similarity, even when they hold entirely opposite views. That collateral damage is neither necessary nor desirable.