Forget about a religios exemption and have a merit test for specific charitable exemptions
The money donated to a church or non profit that actually feeds,clothes or shelters the needy. Actual costs of healing ill people or operating clinics. Thats it. Teaching them to read while indoctrinating them should not count. Any kind of enforcing of evangelical interest would disallow exemptions. Religion or any non profits cannot just wipe their tax slate clean by those designations. Yep its more complicated I guess they could prove their true charitableness by doing things with no benefit to them.