You too are entitled to your opinion, but not your own facts.
But the real problem is that it is part of a broader agenda, to normalize homosexuality. I give you Canada and their suppression of free speech for an example. do some research.
And as part of an agenda, any specific idea, by itself, might not be so bad. But taken together unopposed, they will steamroller not just social conservatives, but libertarians, too.
But live in your dream world.
Your argument isn’t one against gay marriage then so much as it’s against the federal system telling you what you can and can’t do as a business owner, that’s a different argument entirely.
Your complaint is that as a business owner you would be forced to supply health insurance to gay couples under your employ, that’s a by product of federal laws forcing you to do so, and that’s something Libertarians are actually against.