|Indiana Governor Mike Pence|
This is nothing new. For centuries, American slave-owners used their religious scriptures and theology to justify their right to own people as property. After the issue of slavery was resolved 150 years ago by a bloody civil war, the former slave owners continued to use their religion to justify discriminating against black people and their right to vote, to attend any school, to use the bathroom, go to a restaurant, or marry a person of a different race.
Virtually everyone in America now accepts that no one has the 'religious freedom' to discriminate against people of another race. You may have the 'right' to have racist thoughts, but you don't have the right to discriminate in the public square of business, government, education, health care, etc. Intolerance of this kind is now unacceptable in this society and outliers are considered social pariahs and bigots.
Now the scene has shifted away from race to sexual orientation, and the same thing has happened. Discrimination against a socially despised group--in this case, gays and lesbians--that has for centuries been justified by religious dogma, has now become unacceptable, and attempts to continue that social behavior are being repudiated by powerful social forces (American business, in this case) in a sudden, quite unforeseen way.
Sure, those religious people who want to continue to discriminate against gays and lesbians in their pulpits and churches will still be able to do so if they wish. They won't have to perform same-sex marriages. They won't have to ordain homosexuals. They won't even have to accept them as members or take their money in the offering plate. That is surely a guarantee of the First Amendment, with its language of "free exercise", although personally I find it unfortunate that religious people would want to continue to discriminate in this way.
But that understanding of 'religious freedom' has its limits. And the recent experience of Gov Mike Pence in Indiana seems to be further defining what those limits are.