Fascism is not exclusive to the far right in the 20th century it was practiced mostly by the socialist/communist regimes.
Merriam Webster defines it as "a political philosophy, movement, or regime (such as that of the Fascisti) that exalts nation and often race above the individual and that stands for a centralized autocratic government headed by a dictatorial leader, severe economic and social regimentation, and forcible suppression of opposition"
What is considered right/far right in the US is quite different than that. The US right values individual rights over state rights in most scenarios (Aka Classical Liberalism). The US right however does believe in an orderly society and typically uses societal pressures to maintain order. That being said the US right wing and European right wing are drastically different things. The US right would consider the Germans & Russians in WW2 as far left because of the socialist/communists governments and from the US point of view both Ideologies are fascist because they stomp on the individuals natural god given rights. National pride is not a bad thing if handled correctly. But when bad actors add race to it it becomes an issue.
In response to Simon Says
Is antifa far right? NO, quite the contrary. NO, Its far left which has killed nearly twice as many people as the European far right "Which from a US point of view is still far left" in the 20th century
-Is antifa authoritarian ultranationalist? NO, quite the contrary, it's anarchic/libertarian and if anything, anti-nationalist. I agree here except on the libertarian part typical libertarian ideology does not try to force people into categories. They just want to be left alone antifa is forcing a Marxist world view and you have to fall in line or else
-Is antifa dictatorial? NO, it's decentralized, there's no leader. WRONG!!! The IDEOLOGY demands obedience to undefined fluid rules that in and of itself is dictatorial
-Is antifa forcibly suppressing all opposition? Here's a maybe, but considering their "opposition" is fascism, it's not ALL opposition ( as was the case in fascist regimes ). So all things considered in context. NO. Wrong again calling something you don't agree with fascism does not make it fascism. They are a Marxist group that wants power to silence dissenters.
-Is antifa advocating for a strong regimentation of society and the economy? Considering their decentralized nature and that such regimentation has to come from a highly authoritarian centralized power, we have another NO. It would be against their anarchic/libertarian nature. Wrong again. They are Marxists which by definition advocates for a strong regimentation of society and the economy