First of all, in the last generation or two the cart has been following the horse. There have been many SCOTUS and State SC decisions which have not been agreed upon my the majority of people. Liberal-leftists have specifically been using court decisions from on high to force their agenda on the sheeple, who gradually get used to them, figuring that the black robed judges are super human, or that our Constitution gave them some kind of supernatural powers to rule us without representation.
So I totally disagree with this point. For you to say that every or even most court decisions are just following popular opinion is completely false, and flies in the face of the outrage and justified anger about so many SCOTUS and circuit court decisions. In fact, in CA (for example) the courts have overturned referenda voted on directly by the people. IOW, the courts have decided that the legitimate votes by the majority of people (who voted) wasn't worth s**t and a handful of black robed buffoons get to tell 37 million people what to do.
Until and unless we convince people that homosexuality should be considered a disorder rather than a 'normal' condition (even if only for a minority, just as only the minority has blue eyes), there is no Constitutional basis for refusing them whatever secular privileges other citizens receive.
That is also unnecessary. Gay activists and their willing handmaidens have tried to convince the people that homosexuals are a legitimate minority such as blacks or Asians, which anyone who has the slightest desire to see reality knows is a crock, since same sex acts are a voluntary and chosen behavior. Even someone with same sex attraction doesn't have to follow those desires. And the fact is that there are ex-homosexuals. There are no ex-blacks.
So to follow your logic, special rights (such as the right to marry/have civil unions, adopt kids, whatever) MUST be given to adulterers, bisexauls, transvestites and transgendereds, incest afficiondos, "swingers", polygamists, bondage lovers, electicity devotees, and ultimately pedophiles. There is no rational reason not to, since these are all groups whose only distinguishing characteristic is how they like to derive sexual gratification. And that is also the only distinguishing characteristic of "gays". Unless "gays" are more special than those others groups for some mysterious reason?