The Church of Satan has openly stated that it wishes to destroy Christianity by supporting church taxation.
To continue... The Devil does not sleep. He and his servants do all they can to destroy our beloved Church. We live in the End Times. We witness the final war between good and evil. Now God's enemies decided to give His faithful children the final blow. We must now pay huge taxes. The government infiltrated by the Illuminati hopes that our religion falls. But you, dear brothers and sisters, you will not let this happen! God's kingdom is in your hands! Please, rescue it! (Donate more money!)
Even if the churches are taxed (which I doubt will happen because governments and churches usually support each other) I can imagine the appeals to people to donate more money, because the Church is in danger. And people will donate more. There are other groups who support church taxation, I believe. But it would only strengthen the churches and make people even more fanatical, because they would feel endangered and they would have an enemy.
The fact that some filthily rich clergymen will be forced to pay taxes is not going to destroy Christianity. It is a shame that there are holy cows who are exempted from the taxes that ordinary citizens have to pay. However, it is not only a problem of the tax privileges but also some holes in the taxation system, which many "clever" people use to avoid paying taxes.