Nonsense.
If you have a secular law that gives people special treatment on the basis of religions' tenets, then secular courts will have to rule on:
- what is and isn't a genuine religion
- what is and isn't a genuine tenet of a given religion
... since those questions form the basis of what secular rights and privileges the person is entitled to.
‘Golf Religion’ From Japan Stymied in U.S. (Published 1975)
The Japanese church of golf was ruled not to be a religion (so not tax exempt).