Because the USSR was "authoritarian" and that makes them right wing.
Political Science is a real field of inquiry and Political Scientists are real scientists who deserve to be taken seriously, and other lies.
The shit political scientists say is just baffling. Like whether you like the USSR or not, defining right wing politics as being "authoritarian" is just bizzarely ignorant and weird. And, like, the definition of a nation state is partially an entity which effectively monopolizes the legitimate use of force within it's borders, so what the fuck does authoritarian even mean? Authority is the definition of a state, it's what makes a state a state. Fucks sake.
Anyone who uses the word 'authoritarian' sicnerely should be dismissed as a fool immediately. It's also fun to ask where the line between acceptable authority and authoritarian is to them and then describe an example of it happening where they are or they'll.just describe probable falsehoods regarding the authoritarian we like that clearly mark them as different than the Hitler authoritarian because the term is simply a crude cudgel to bash two different shaped blocks through the fascist shaped hole