There was & is a reason that churches are not subject to taxes. The Founder were concerned that the government could influence what the churches / Pastors of the churches would say by using the hammer of taxation. They saw this in Britain & Europe & did not want it to happen here.
This is why they put in writing that the Freedom of speech & Freedom of religion were in the same Amendment.
This is also why both are in the 1st Amendment & not one of the latter ones of the Bill of Rights.