I understand your passion (conservative Christians piss me off too), but there’s a big difference between a Texas Baptist who wants the legal right to exclude queer people and say, Bishop Gene Robinson and his husband, members of the Episcopalian Church.
The problem isn’t so much free exercise, I think, as the redefinition of free exercise to extend from the private sphere to the public one.
The balance has traditionally been one of imposition. In other words, forcing others to follow one’s own beliefs has been judged to cross the line of free exercise.
That’s the legal argument. Many progressive Christians make a theological one. They say that excluding people from love and community isn’t free exercise because it actually runs counter to Christian faith.
That’s what Bishop Robinson would say, anyway.