There are many arguments that can be made about this issue, but for me the biggest one is that it impinges upon the First Amendment rights of free exercise of religion. If gay marriage is found constitutional that how can any pastor of any church refuse to marry gays or hold gay marriages in their churches? The same would be true of any religious person who has a bakery or a photography business, etc. They will be accused of discrimination and this will open the door to all kinds of lawsuits. The right to object to being forced to do something based on the exercise of individual conscience will be gone. And even if it survives, the amount of money it will take these people to defend themselves will put them out of business. Can you imagine how the Moslems will react to this kind of thing?
That will never happen, even if SCOTUS holds there is a constitutional right to gay marriage. No case has ever required a Catholic priest to marry someone who has a civil divorce but not a church annulment. No case has ever required an orthodox Rabbi to marry a Jew and a non-Jew. If there is a right to gay marriage, it is a right to a civil marriage and to a marriage in any church willing to do it.
The same would be true of any religious person who has a bakery or a photography business, etc. They will be accused of discrimination and this will open the door to all kinds of lawsuits.
That is a different issue. A few states have already had lawsuits on that basis, where state civil rights laws forbid discrimination against gays in "public accommodations." I think those cases are wrong, but your fear is much more likely to materialize there.
The right of churches to “opt out” has been destroyed via healthcare.
The road to hell has been carefully and deviously paved by liberals.
Deconstruct the Constitution little by little to where is no longer means what was written.