Actually, in other nations, like in the U.S., it would only be people that object to that persecution of Christians that would even be likely at all to find out more about it and why it's happening. So, it's those that object that will do the work to learn more.
Here's an example of what I'd see when searching up more about this from a quality source:
"In 1867 an English missionary, James Hudson Taylor, wrote a letter home defending his policy of encouraging fellow preachers in China to wear Chinese robes and the Manchu-style pigtail. By dressing in Western garb, he argued, they risked giving the impression that becoming a Christian meant becoming a foreigner. Taylor’s concern was justified. Such was the scorn for those who embraced the faith that, long before the Communist Party seized power in 1949, people used to say, “One more Christian, one fewer Chinese.” Officials in China still mutter this phrase today.
In the 1950s the party began cutting Chinese Christianity’s links with foreign churches and requiring believers to worship only in government-authorised venues. Eventually all religious activity was banned and brutally crushed. A few years after the death of Mao Zedong in 1976, restrictions were partially relaxed. This led to an explosion of Christian worship, much of it in small “house churches” with no official links. ....
China wants to make its Christians more Chinese
So, the reason God might feel like a threat to the controlling Party is that the Party doesn't control God, and it may turn out that a citizen that believes in God will not
worship the Party.
They might see the party as being compose of people that are
only human, and not perfect, and not put their faith in the party for the main guidance in their lives.
While this would actually help China, and even create a more thriving society, it could feel like a threat to a Party that is doing something wrongful and wants to control all thought.