Part II:
And if SCOTUS sides with Masterpiece Bakery, the conservative Christian viewpoint will prevail over other religions in matters of how the law treats gay people.
Conservative Christians will be able to discriminate against gay people, by proclaiming religious or artistic freedom, but conservative Christians will be protected from discrimination by the very same civil rights laws conservative Christians want to deny to gay people.
Also, as at least one judge has pointed out, people who claim no religious freedom right to discriminate against gay people could still, in theory, be subject to civil rights laws that include sexual orientation. Of course, the result will be that everyone who doesn't like gay people will simply claim religious freedom. But gay people won't be able to claim the religious freedom to discriminate against Christians.
This is all about power.
Conservative Christians want the right to have an exclusive monopoly on what is moral -- backed by the government.