The issue I think arrives when there is an unwillingness to tolerate people who hold intolerant ideas, views, or beliefs, even when those people do not act on those ideas, views, or beliefs - i.e. when the people with intolerant views are not actually practicing intolerance.

It's one thing to shun a customer for practicing intolerance, it's another to shun a customer for holding intolerant beliefs without actually practicing intolerance or materially affecting the quality of life of anyone around them, is it not?

Someone who takes no actions based on their beliefs effectively doesn’t hold those beliefs, as far as anyone else knows, and doesn’t get shunned for them. So you’re trying to define some level of advertising your beliefs as “not acting on them”. What’s that level? An op-ed on the problem of gay people, or just a casual remark that of course gay marriage is a sin?