There is often confusion about what exactly people are entitled to when it comes to opinions. Certainly people are entitled to hold whatever opinions they like - even people holding the most offensive an awful beliefs I can imagine are entitled to hold those beliefs. However, the reasoning that everyone is entitled to their own beliefs is far too often used to justify changing public policy. You are entitled to think anything you damn well please, but if you want to alter public policy you had better be able to prove that the policy you want is based on facts and will actually help other people.
You want to hold the opinion that gay relationships aren't as worthy as straight ones? Cool, hold that opinion. I will hold the opinion that you are a grade A shithead and we can have fun holding our opinions together.
You want public policy to penalize, refuse to recognize, or otherwise disenfranchise people in same sex relationships? Sorry, no go.
Feel free to substitute anti vaccination stances, transphobia, sexism, racism, climate change denialism, or any other variety of bigoted or uninformed nonsense in the sentences above.
Not only are you not entitled to set policy, you aren't even entitled to a seat at the table. Not all opinions are equally valid when making policy decisions and nobody is required hear out opinions that are based on faith rather than facts or hate instead of tolerance. You might well be able to get a seat on a news program where they compare somebody representing established truth vs. fantasy and pretend like those are two equally valid standpoints but that is luck or politics, not a right.
Your right to think whatever you want inside your own head is absolute and it is something I will fight for even when the views you hold are reprehensible. But your right to hold those views ends where they negatively affect others so if your views are going to hurt people and/or have no basis in reality then you had best be prepared to sit down and shut up when it comes time for all the grownups in the room to make real, important decisions.