The exemption of churches, synagogues, and other religious organizations from taxation is a longstanding principle of American law that has recently come under attack. Richard W. Garnett defends the practice:
Instead of asking whether churches and religious organizations deserve to be tax-exempt, we should ask why governments should be able to tax them at all. Taxation, after all, involves interference by the state, and in a free society such interference needs to be justified. . . .
Many of the recent calls to tax churches rest on the premise that churches owe at least some of their resources to political authorities—to governments—who can decide whether or not to collect and use those resources for their own purposes. In this view, exempting churches from taxation is seen as somehow subsidizing religion. But it is a mistake to equate “not taxing” with “subsidizing,” even if in some sense the effect is the same. Governments do not refrain from taxing religious institutions merely because it is politically convenient or socially acceptable to support them. They do and should continue to refrain from taxing churches because their power over them is limited, because “church” and “state” are distinct, and because religious freedom is fundamentally important.
Read more on Washington Post: http://www.washingtonpost.com/news/in-theory/wp/2015/09/15/religious-tax-exemptions-protect-religious-freedom-we-should-keep-them/