Check out the motivation!

[daaron]

31. Here is some -->

http://caselaw.lp.findlaw.com/data/constitution/amendment01/04.html

Looks like the tax code was set up to apply to all non-profits including religious bodies in order to apply a secular standard. That is, to give the exemption only to religions would violate the Establishment clause, so we don't do that. The entanglement doctrine applies here, too.

...termination of exemptions would deeply involve government in the internal affairs of religious bodies, because evaluation of religious properties for tax purposes would be required and there would be tax liens and foreclosures and litigation concerning such matters. 135

While the general issue is now settled, it is to be expected that variations of the exemption upheld in Walz will present the Court with an opportunity to elaborate the field still further. 136 For example, the Court determined that a sales tax exemption applicable only to religious publications constituted a violation of the Establishment Clause, 137 and, on the other hand, that application of a general sales and use tax provision to religious publications violates neither the Establishment Clause nor the Free Exercise Clause. 138