It's not up to private businesses. They are (of course) merely collecting taxes as required by law. No private organization has the power to exempt anyone or any organization from paying legally obligatory taxes.

As to your comment about property taxes, yes ... this is what I've been saying all along. Since religions are merely sets of ideas people choose to believe, then privileging religion as a very special category of identity -- as we do today -- is a very, very bad idea.

How do you decide what's a "valid" religion and what's not?

Tradition?

Well, that leaves Mormons out. Their religion was invented (in a particularly absurd and unbelievable manner) just a very short time ago. Other new religions are even younger (and more radical) than that, like those racist neopagans.

Popularity?

That would leave out some ancient religions that are barely practiced in the U.S. Think Zoroastrianism, Polynesian paganism, or even Sikhism.

Establish expert panels to rule on what's a valid religion and what isn't?

I don't think I need to explain how subject to political abuse that would be!

No, the solution is to not elevate any religion to a special status. Treat all human ideas equally, by their merits, religious or not.