For all its flaws and mistakes the U.S. was nothing like the Soviets, not even close, not even now.
Can you provide an example of something that the Soviets did that the United States has not done?
Read up on the Stalin era. Even later Soviet leaders were disgusted.
While you're formulating your answer, consider that the United States is the only country to nuke another country.
And in the odd perverse mathematics of war may have saved lives compared to blockade and starvation or invasion and mass casualties by conventional weapons. The simple fact was that Truman was expecting 500,000 American dead and 5 million Japanese dead if the war continued through conventional means. The atomic bombings were a tragedy, the problem is that the other options may have been far worse. A classic negative-negative decision, all your likely options are bad.
The casualties from mass fire bombings in Tokyo were comparable to an atomic bombing. Read Eugene Sledge's "With The Old Breed" for an account of the fighting on Okinawa. President Truman had such accounts in his mind when he made the decision. Also note that civilian casualties on Okinawa were comparable to an atomic bombing. I realize it is popular today to say that Japan was going to surrender anyway but the historical facts are that the surrender after the atomic bombings and after the emperor's decision nearly failed when a military coup was attempted. The plotter's had to "rescue" the emperor from the bad advice his ministers were providing and prevent his surrender message from going out. We have no idea what would have happened without the atomic bombings, imminent surrender is hardly a foregone conclusion. Again, Truman faced a negative-negative decision, he had no good option, rather one option that may produce fewer casualties (military and civilian) than the others.
We used our own prisoners and citizens as guinnea pigs to conduct experiments in nuclear, biological, and chemical warfare.
We engaged in propaganda in the extreme, rewriting our pledge of allegiance to include "under god" and printed the same on our money as a propaganda war against "godless communism."
Seriously? This is some great and terrible crime?
We engaged in witch hunts, like McCarthy appearing before Congress to say he "held in his hands" a list of known communist co-conspirators.
McCarthy was a buffoon. The anti-communist witch hunts wrong. But you are making my point for me. These witch hunts were nothing like those under the Soviets. Read up on Soviet gulags.
We publicly executed Julius and Ethel Rosenberg in 1953, and it wasn't until just a few years ago, in 2008, that the transcripts from a court case widely panned at the time as a "witch hunt" revealed major inconsistencies in the testimony of key witnesses against them.
Decoded 1944 Soviet cables confirmed Julius worked for the Soviets. Nikita Khrushchev wrote in his memoirs that they helped accelerate the Soviet atomic bomb program. Various Soviet officials eventually confirmed that Julius was a wartime spy.
They had only passed on low value information that was already duplicated elsewhere... mostly hand-drawn sketches.
Primary source or merely a secondary confirmatory source, large contribution or small contribution, its still wartime espionage. Was the penalty excessive, perhaps, but executing a wartime spy is hardly in the same category as executing those who disagree with a government policy, as we saw in large scale during the Stalin era. Again, you are merely confirming the US and Soviet governments were nothing alike. No one is claiming the US government was without flaws and mistakes, just nowhere near the Soviet level. Enlightened leaders like Mikhail Gorbachev were the exception not the rule.