The problem of the US foreign policy is that, they like tailor make a dress then they want the world to wear it, however,no it won't fit.

Gay, bi or lesbian or straight, it's up to people to decide? The US can't be the role model for everything.
Look how many years did it take for women suffrage?
What happened to the Indians (native Americans) ?
What about African Americans and the civil rights movements ? and the list goes on and on.

US first amendment and the establishment clause suggests the idea of "Separation of church and state" however that's not the case in every country, nor that every country would favor this.

Everyone is free to do what they want just don't impose any resolution under the international community to do so.