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.
I have no idea what they teach in political science classes, but I honestly think that they could get a better understanding of politics from playing Paradox games than whatever they teach in them. The way they talk it just seems to be "ignore every single actual bit of useful information about politics and use big words to cover up the fact that you have a toddler's understanding of politics."