The Chinese government is indeed suspicious of Islam, and rightfully so, but consider Christians to be more or less harmless. Yes, if a church gets too big, they break it up (which just creates more churches,) but nothing to the extreme level of monitoring suggested by this article.
The reason is straightforward: Unlike Islam, Christians have no interest in taking over their government, they just want to grow the church over there. The government sees Christianity as kind of like a harmless fad the people will eventually forget about. The truth is, the church is growing like crazy there.
Source: a good buddy is a missionary in Beijing, has been for 8 years. He went from preaching, to church planting, and is now in a leadership role within a mission board.