The government wants to maintain power at all costs, what's best for the country and it's citizens is irrelevant. If a large number of Chinese begin to value the word of god more than glorious leader Xi, that's a threat to the status quo.

They have plenty of people, last I heard. Plus or minus one million people here or there doesn't really make any dent on their society and getting rid of "undesirables" without mass murder looks very beneficial in the eyes of the authorities.