Pray tell, how does the US qualify as an empire where the USSR did not?
As regards Afghanistan, undermining a popular revolution by arming feudal lords and then benefiting from vast quantities of cheap opium (which the government they were undermining was trying to stop production of) is imperialistic. As is taking over and enriching your ruling class on the flimsy pretense that Osama Bin Laden was in the neighborhood.
Trying to stop the United States from overthrowing a popular revolution is not, though there is
some benefit to not having a bunch of warlords and religious fundamentalists in control of a country next door.
As regards the rest, the Soviet Union existed under the pressures of global capitalism and because of that could not simply become the largest hippie commune in world history. The discipline of the market which governs which firms succeed and which fail also applies to states: both must generate surplus value in order to survive. Firms must reinvest that surplus into more efficient production processes while states must do that and also invest in military preparedness. The Soviet Union could not ignore such pressures without a worldwide revolution.
(outside of the USSR claiming to support but not actually practicing your political beliefs)
You apparently think that the Politburo was filled with the likes of Jeff Bezos and Bill Gates, so I can't say I have any care what your thoughts are on whether the Soviet Union practiced my political beliefs. I don't think what they did resembled what I would have for the United States, nor that they reasonably could have done anything like that because of their different material circumstances. But they did have a lot of successes that we can learn from and made many mistakes that we can learn from (chief among them the failure to change the organization of production to one in which workers democratically control their workplaces; on the other hand, I suspect that such a move if performed from the beginning would have resulted in the Soviet Union ending by 1941 at the latest for the very obvious reason you'd think of upon seeing that date).