Can you define fascism?
USSR was famously anti-religion (criteria 8) and pro labor (criteria 9 and 10) so thinking USSR shared 80-90% with Nazis is kind of laughable.
Fascism is more then authoritarianism. It is a set of explicitly right wing and explicitly anti-communist and anti-socialist policies, fascism is extremely pro-business. And it is explicitly racist and nationalistic.
The Soviet Union was explicitly pro-worker, it was explicitly communist, it was explicitly left-wing. Under its first ruler it was even explicitly internationalist (to the extend that the Internationale was their national anthem; But their second ruler was for sure a nationalist). There is no definition of fascism which includes the Soviet Union. If the Soviet Union were fascist, then fascism becomes a useless term completely synonymous with authoritarianism.
If we were to consider the Soviet Union fascist, simply because of their atrocities, than we would have to consider the British rule over India fascist. And there we also run into problem, because the British also fought and defeated fascism (albeit not as decisively as the Soviet Union; leaving fascists in power in Spain and Portugal). And there is even more of a case for fascist UK because unlike the Soviet Union, the British enacted racist ethnodemocratic policies emblematic of fascism.
But we have another name for the types of government which ruled India in terror. And that name is Colonialism. The British government wasn’t fascist, it was colonial. And it committed their numerous atrocities in India under the ideology of colonialism.
Likewise with the Soviet Union. At no point in their history were they ruled by a right wing, pro-business, pro-religion, racist regime. The Soviet Union committed their atrocities not to enrich the business elite, with some ethno-nationalist/religious ideology, but to further the ideology of Communism. Businesses were state owned, education was universal, and unions were elevated. The party elite then put them selves in high paying positions for the state owned businesses, created better schools for their own children, and pushed union leadership loyal to the party. So corruption for sure, but still not fascism. For that we need the unions disbanded, their union leaders executed, ethnic minorities kicked out of schools and into ghettos, and state corporations handed over to the aristocracy, etc.
I am also gonna add, that you are arguing from a very weird position that has no support in academia, nor from most people.
>> 1. Powerful and Continuing Nationalism
>> 8. Religion and Government are Intertwined
>> 9. Corporate Power is Protected
>> 10. Labor Power is Suppressed
Saying that any of these points applied to the Soviet Union at any point in its history is ahistorical.
In addition we have nuanced points like:
>> 2. Disdain for the Recognition of Human Rights
This was true for a small period during Stalin’s purges but under Khrushchev the human rights record of the Soviet Union was on par with other (non fascist) European colonizers like France. If we were to consider this true for the Soviet Union we must also include France under Charles de Gaulle to be fascist. But again we have another name for the ideology behind these atrocities: colonizer.
Note also that there was a Fascist colonizer in Western Europe for most of Soviet Union’s history. And that was Portugal. Are you telling me that what made Portugal fascist, could equally apply to the Soviet Union? Nobody thinks so, probably not even you.
Also note this point:
>> 3. Identification of Enemies/Scapegoats as a Unifying Cause
This was true throughout the history of the Soviet Union, but an important distinction/nuance is the unifying enemy of the Soviet Union was Fascism and Western Imperialism, and not The Jews, Feminists, or Collage Campuses. The latter three are indication of fascism, the former two are indication of most centralized states.
The word you are looking for is authoritarianism. Tankies and the USSR were and are both authoritarians (the former also by definition). Note also that modern Tankies share a lot more with fascists (both historical and modern) then the USSR did, most notably nationalism, the belief in strict social hierarchy, conspiracy theories (mostly of an enemy that is weak enough to squash like a bug, but at the same time strong enough to end civilization), and general bigotry.
Note that on the left we also have Nazbols who, in addition to all the crap tankies belief, they are also racist ethno-nationalists. However just because the left also has racist bigots (albeit not nearly as many as the right) that still doesn’t make them fascists. To become fascists they would need to become pro-business capitalists and start blaming communism for everything what is wrong with the world.