Well, the US did some pretty bad things to its own people.
Trail of tears, slavery... I wonder how many people have died at the hands of the US govt in the US.
Also, when China "killed" lots of people, mostly it was due to starvation. Yes, stupid policies led to this.
"How Many Deaths Did The Great Depression Cause?"
"The Great Depression, a severe global economic downturn from 1929 to 1939, began in the United States and spread worldwide. Four factors played roles of varying importance: the stock market crash of 1929, structural weaknesses, specific events that turned it into a major depression, and how the downturn spread. The exact number of deaths directly caused by the Great Depression is difficult to determine, but it is estimated that around 5-10 million people likely died during this time."
5-10 million people.
For a country whose population is like 4-5 time smaller than China, in actual fact the number of deaths are pretty similar.
So... I think you're wrong. The difference is how each has been reported.