Nazi Germany and Fascist Italy were right wing fascists because they embodied traits associated with those ideologies; nationalism,
Nationalism is a form of collectivism, and while Lenin said he was opposed to it, many other famous commies have been nationalists - Mao was a nationalist, as was Pol Pot. The pledge of allegiance in the US was written by a socialist - Francis Bellamy. Progressive hero Teddy Roosevelt was also a nationalist:
en.wikipedia.org
Commie Ho Chi Minh was a nationalist:
Nationalism is not right wing.
The military itself is a socialist institution - it is public ownership of means of production regarding national defense. National defense is a
public good:
If we define militarism as "the belief or the desire of a government or a people that a state should maintain a strong military capability and to use it aggressively to expand national interests and/or values", then many commie countries fit. The USSR, North Korea's policy of songun, Venezuela under Chavez, and note how all the commie dictators Bernie Sanders luvs are always dressed in military garb.
In short, there is nothing "right wing" about militarism, and the loudest voices against conscription are those on the far right,
while leftists luv the idea.
The Bolsheviks were imperialists:
en.wikipedia.org
China was and is imperialist:
en.wikipedia.org
Imperialism has been going on for millennia, and to claim that it is "right wing" is absurd.
Nazi Germany and Fascist Italy were right wing fascists because they embodied traits associated with those ideologies; nationalism, militarism, imperialism
To summarize: nationalism, militarism, imperialism, are not right wing. Nationalism is form of collectivism, and militarism is socialism, both of which are core left wing ideals.
while rejecting Marxist principles like the abolition of private property
Fascists were extremely hostile to private property. Both Hitler and Mussolini could not have have done what they did if either of them recognized and respected private property rights.
and the class struggle above all else.
Here are some words from Marx regarding the class struggle between the workers and the greedy bourgeois business owners:
"Therefore it is evident that if the individual workman is to have any chance at all of winning through in the struggle he must be grouped with his fellow workmen and present a united front before the individual employer, who incorporates in his own person the massed strength of the vested interests in the industrial or commercial undertaking which he conducts... It was difficult to discuss this problem with the average bourgeois employer. He had no understanding (or did not wish to have any) for either the material or moral side of the question. Finally he declared that his own economic interests were in principle opposed to every kind of organization which joined together the workmen that were dependent on him."
Oh wait, that's not Marx, that's the "right winger" Adolf Hitler, and note that Mussolini would wholeheartedly agree with the above, since he was a socialist for his entire life.
It's almost like there's an actual set of political beliefs and standards that are associated with specific ideologies and movements.
There are differences, but the differences between communism and fascism are trivial. Diarist Victor Klemperer had the misfortune to live under both, and he found little difference between the two.