The ideological roots of the far-left and far-right are ultimately grounded in European-born ideologies (Marxism/Nazism/Fascism), and since a lot of them lack political or financial capital, or more importantly: an imagination, they wear the skins of old ideologies that were fit for purpose of their origin countries in decades past; trying to apply them to a modern, foreign mould 1:1 doesn't really work in much the same way you can't connect a PlayStation 5 to a television from 1951. You can make derivatives, or seek inspiration, but neither far-left or far-right are really creating ideologies with American consideration in mind.
America possesses its own national characteristics that the likes of Fascism and Marxism are in opposition to, and which when the state embodies the opposite of, pisses people off. America is, as perceived by this Brit:
1. Free.
2. Fair.
3. Fecund.
Taking away or suppressing individual freedoms; not being fair with opportunity or not regarding everyone equally; or forcing people to be content with less than what they already have is anti-American.