It’s typical tribalism and labeling.

Tribalism makes those people put them-alike above others.

Labeling makes them wash the humanity of other people and mark/group them using some nasty word, e.g. some lefts calling some rights - “nazi” and rights responding with “commies”. Fun fact- in both cases most don’t understand the meaning of the word they use and when questioned why they call those ppl like this quickly get lost.