Gotta partially disagree with you NC.
Tax exemption is a privilege, not a right. To earn this privilege, at the moment, all you have to do is claim to be a religion and if the government agrees that you are in fact a religion, then you are tax exempt.
A bit of responsibility should be required on the part of any organization that wants to be tax exempt.
If you want to shun ex-members, tell homosexuals they can't join, be sexist, racist or otherwise unamerican, that's your right and nobody should stop you. But not if you want to be tax exempt.
Ideally the requirements should include: Contributing beneficially to society through charity, education or other.
But for now: Not being evil. Is a decent first requirement.
I don't see how this is more unconstitutional. At the moment we are giving religious organizations a financial advantage based SOLEY on the fact that they are religious. There is no constitutional justification for that.