Within the countries? Yes, China is the worst. In relation to the world? The US is the big bad without even real competition. Also the core of the argument was that the world is full of crimes and violations of human rights perpetrated by a lot of countries, it's only when it's convenient to the West that morals and principles become important, but for any sanctioned country there is 1 that does the same and is safe, because they are aligned with the West, or worst, because they are not considered strategic or important and are ignored in consequence.

If it was about morals or lives trade with world powers, specially the US would be impossible. Reality is that at the end of the day, moral arguments are just a tool used in economic conflicts to justify whatever is convenient to the accuser.

Not really. Diseases did most of the job. The Spaniards where not really interested in killing millions of people that could be useful. Sometimes the Europeans didn't even need to arrive at a place to exterminate a population, like the people of the Mississippi valley, an advanced civilization with big towns and agriculture, diseases arrived and collapsed that society, by the time the Spanish people arrived only empty towns remained, by the time the French and British arrived nothing was left.