Well it really depends how we define fascism. If we can define Trump as a fascist and both TPUSA and YAF promote pro-Trump propaganda then they would be fascists.
Here's the wikipedia entry
Fascism (
/ˈfæʃɪzəm/) is a form of
far-right,
authoritarian ultranationalism[1][2] characterized by dictatorial power, forcible suppression of opposition, and strong regimentation of society and of the economy
[3] which came to prominence in early 20th-century Europe
Lets focus on the bolded (far right and ultranationalism) the
authoritariansim and
forcible suppression come in the later stages as the fascists consolidate power, but we are already seeing the beginnings of this under Trump
Ultranationalism according to wikipedia
Ultranationalism is "extreme
nationalism that
promotes the interest of one state or people above all others"
I want to look at both ultranationalism in terms of state and people
1) state - "America first" Trump clearly advocates the interests of the USA and Israel above other states, in an extreme fashion where he doesn't care about the welfare of any other state, and will pursue policies to the extreme detriment of other states
2)People - Trump is clearly pushing a soft form of white nationalism by demonizing muslims, mexicans, immigrants, blacks, and pushing various forms of white nationalism. "build the wall" "islam is at war with us" "mexicans are criminals and rapists"
TPUSA and YAF both push propaganda which enforces these ideas of external and internal threats to "real americans" and I think we all know what that means.
Also Fascism is not something that comes overnight, it is a drawn out process which goes through various stages of indoctrination and the moving of the overton window.
You have propagandists like TPUSA and David Duke basically pushing the same message (anti-immigration) but with varying levels of radicalization. Obviously TPUSA is offering a much more watered down message than David Duke, but they are essentially saying the same thing, which is essentially this
The USA and "Western Civilization" is under attack by Leftists and progressives who wish to see it all burn down and are forcing immigration and political correctness down our throats, which we need to fight back before we exist no more.
That is fascism. The creation of external and internal threats which represent a grave threat to the "in group" (whites, conservatives, christians) and the movement to neutralize those "threats" which are nothing but scapegoats for the problems created by the elites Neoliberal/capitalist economic system.