Would you rather that America accepted 50 million immigrants from China or would you rather that China accepted 50 million immigrants from Africa?
Keep in mind, there would be consequences for either choice...
For example of possible results/outcomes...
If America does not accept the 50 million immigrants from China then China would probably be mad at America.
If China accepts the 50 million immigrants from Africa then China might become very strong allies with Africa... or other things could happen.