Yes, when it comes to atomic atrocities, the United States is vastly more culpable than any other nation state. The Soviet Union excelled in different realms, such as imposing starvation (Ukraine), halting movement (all Soviet republics), and restricting information (all) on its vassal states.
To be fair, the latter realms are very much within the reach of any autocratic state; its just that not many are either foolish or powerful enough to make use of them.
