Your assumption is that economic cooperation makes "evil" countries become more like the "good" countries they cooperate with. I don't think that holds true. Just take China and Russia, who have very strong economic ties with almost all of the world. Human rights in Russia certainly are not getting any better, and I doubt they are in China. In fact, taking recent relevations into account, those ties might just as much be corrupting the "good" countries, and not (just) working the way you assume they are.
While these countries are definitely more oppressive and have less human rights than much of the Western world, do you really think that they've haven't gotten better in that regard with greater connections to the West? I don't think many would agree that these countries had better human rights and living conditions a couple decades ago.
As others have pointed out international pressure was instrumental in dismantling Apartheid in South Africa. That is one clear example.
As said, with Putin, I think things have only gotten worse. And China seems to be settling on a benevolent dictator, too, these days. So at least recently, I don't think things are getting any better in those two countries.
