A commenter noted:
"I'm sure some will call it unconstitutional, but I believe it's high time for the IRS to explicitly define what a "church" really is."
Yes. That's unconstitutional. The last thing the government should ever do is decide who is or is not a church or what is a religious organization and what is not. Scientology gets tax exempt status whereas various Humanist organizations get told they aren't a religion and many small religions are outright denied. It's absolutely unconstitutional to have the federal government deciding what is or is not an establishment of religion.
So you ask, how do we prevent asshats like Mr. Shields here from saying they are churches if there's no governmental overlord? We don't. The government should tax everybody equally regardless if they are religious or not. If you tax everybody equally then there's no point to claiming that you're a church when you're not because there's no benefit to it.
Everybody pays taxes.
That "except churches" line is a law respecting an establishment of religion. It's that silly unconstitutional addendum that forces the IRS to make even more unconstitutional judgment calls as to who is and is not a religion. It shouldn't matter at all. Taxes pay for public services and everybody uses them. Some people here advocated that we should deny this guy public services because he doesn't pay for them. But, what about all the legit churches that similarly use public services and are tax exempt? Shouldn't we likewise tear up their roads? The only proper non-convoluted solution to the problem is to simply everything and tax everybody equally regardless.