I could not agree more. I have long felt that giving religious organizations tax exemptions violates the Establishment Clause. No religious property of any kind should be exempt. This should alleviate the huge burden born by local communities when conglomerates, operating under the guise of "religion," gobble up sometimes huge parcels of land and take it off the tax rolls. That is simply not right. It has the effect of government "establishing" the religion by giving it special consideration and forces the local populace to underwrite its activities, even though some may vehemently object to them.
While we're at it, I believe that no charity should have a tax exemption greater than the amount they actually spend on charitable activities, plus maybe 10% for administrative costs. And non-cash gifts and services received and redistributed as charity should not count towards that amount. If charities had to prove they gave out at least 90% of what they took in, it would cut back a lot on the number of scams masquerading as charities.