Amendment I, U.S. Constitution:
"Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof;"
The IRS code is a law made by Congress. Tax laws, whether to tax a religion or to prohibit political speech because of tax exempt status, is "...prohibiting the free exercise thereof;"
The tax code, as applied to religion's, is blatantly and categorically unconstitutional.
Just because a "benefit" may accrue from a federal law, "...desire to suck at the government teat...," as you put it, the law(s) still cannot violate the Bill of Rights.
I'm afraid that I must disagree with this statement. Certainly, tax laws can be unfairly structured so as to kill off an entity or activity. But in and of itself, simplying applying a tax to an activity isn't considered prohibiting the free exercise thereof. Freedom of speech is another activity that is also protected on this basis, yet putting corporate or sales tax on newspapers isn't "prohibiting the free exercise thereof". So why would taxing a church at rates common to those of other landowners or corporate entities be viewed as such? My understanding is that non-profit entities such as churches, hospitals, charities, etc.., are not taxed because the operation of such entities is seen as a public benefit, and taking their money makes less sense than allowing them to keep it and use it for purposes that are in the public interest. I imagine that this is why there are there are multiple different types of NFP's, so as to weigh the level of public interest there is in allowing them particular tax privileges, and why contributions to them are treated differently (some are tax deductible, some are not). What I don't believe is that NFP's in general, or churches in particular, are relieved of taxes because to tax them would prevent them from the "free exercise" of their activities.