Honestly I think it's more a question of good business decisions. Ethical standards are something that many businesses advertise (like every other aspect of themselves) so even in terms of denying gays services in the name of "religious freedom" can be viewed through the lense of competitive values.
An interesting parallel is that of the restaurant chain Chick fil A.
https://en.m.wikipedia.org/wiki/Chick-fil-A_same-sex_marriage_controversy
They also close on Sundays as Sunday is considered a day of worship. As a business they declared themselves quite strongly in the face of true equality by rallying behind the Christian Values that homophobes tout as truth.
Then again, my lesbian and gay friends still ate there and continue to do so. Why? "Cause it's some damn good chicken."
Haha
Soooo take from that what you will. Some establishments, even big chains, will stand by their principles even if it means risking patrons. But economics is economics. If enough people stopped eating at your place because you hung "God Hates ****" signs everywhere, you'd either go out of business, or take the signs down.
Another thing to consider is that businesses both large and small have to answer to the municipality they exist in. This means appeasing the city or town or county officials that preside over your building licenses and operations licensure. Some towns are staunch opponents to bigotry or restrictions. Like Cambridge, MA. Others are totally opposite, like opposed to businesses being open on Sunday like in parts of the deep South.
Then there's the people. Pretty much never will you find yourself opening your business in an ideal location where there's zero resistance to your preferred business model. There's always some measure of compromise. So where one "draws the line" really depends on the locale and its laws, its patrons and the personal preferences of the business owners themselves. In America you're sure to find every manner of establishment ready to satisfy every type of patron imaginable.
