The only important question in terms of test subjects dying is whether they don't die under some other circumstance. The U.S.S.R and Chinese dictatorships were/are horrendous. On the other hand, Cuba has major ethical problems but subjects dying isn't these days really among them. Cuba does a better job of keeping people healthy and secure than the U.S. does. There's no homeless sick people in Cuba basically. Everyone gets quality medical care even though the country is massively poorer in fundamental resources than the U.S.

The people dying in the cases you are referencing did not die because of the ideas of communism. The atrocities were carried out in the name of communism but had no basis in actual communist ideas.