Ok, let’s take a look at two of your apparent premises:
1. Less Christianity = bad for nation, more Christianity = good for nation.
2. China is actively in the process of turning the United States into a vassal state.
Wouldn’t it logically follow, then, that China would promote Christianity within its own borders? It’s kinda hard to conquer a nation when you are also actively destroying yourself (and you can’t claim they wouldn’t know they’d be destroying themselves, since less Christianity is a cornerstone of their strategy to destroy the United States). It’s almost as if you have no idea what you’re talking about.
I’m not going to pretend that China is any kind of paragon of international benevolence, but American nationalists have no standing to complain about other countries trying to turn us into vassals when the United States has been propping up puppet states in much of the world for the whole of the 20th century.