If an outsider may be allowed to comment ...
It often seems odd to me that in a country based on a secular constitution, with express separation of church and state, religion and the religious have so much influence. Having said that, there is a view that when the Mayflower left England the 'freedom' that the 'pilgrims' sought was the freedom to persecute each other more than they were allowed to do in England.
Various polls show the extent of fairly fundamental religious beliefs in the US. I think I'm right in saying (correct me if I'm wrong) that over 50% of the population believe that the 'Second Coming' will occur within fifty years. That's disturbing (to me, at least) and illustrates one problem with this type of legislation. I am sure that the lawmakers blithely assumed that the 'religious belief' concerned would overwhelmingly be their brand of christianity. How would they feel if, for example, the majority of the population became muslim and it was normal to discriminate against women not wearing burkhas?
There are many wacko religions and as I understand it in the US they are all entitled to equal status. So essentially anyone can justify any discrimination provided that they claim it is in accordance with their religious belief.
It's a good principle when considering legislation to imagine the most absurd circumstances and see how the proposed law would apply.