The question of whether gays choose to be gay or not is beside the point. A person doesn't CHOOSE to be a schizophrenic, but that doesn't make it any less a disorder. Likewise, even if someone doesn't CHOOSE homosexual tendencies, it doesn't mean it is therefore healthy and normal.
No, the reason the black civil rights analogy doesn't wash is because blacks were standing up and demanding rights to which they were already entitled but were being denied. We didn't have to rewrite "All men are created equal." We simply had to demand that Americans extend those rights to ALL MEN. There was no new right or new idenity created. As Martin Luther King, Jr. said:
"In a sense we have come to our nation's capital to cash a check. When the architects of our republic wrote the magnificent words of the Constitution and the declaration of Independence, they were signing a promissory note to which every American was to fall heir. This note was a promise that all men would be guaranteed the inalienable rights of life, liberty, and the pursuit of happiness.American blacks came for what was already rightfully theirs. Clearly, homosexuals are demanding a new right, a new social contract, a new promissory note, one not in the Constitution, but foisted on America by the courts. That is why the analogy breaks down. Not because of what choice one has in their homosexual tendencies. But because no one ever promised homosexuals the right to be married. It's really that simple. At least, to this hetero white male."It is obvious today that America has defaulted on this promissory note insofar as her citizens of color are concerned. Instead of honoring this sacred obligation, America has given the Negro people a bad check which has come back marked 'insufficient funds.' But we refuse to believe that the bank of justice is bankrupt. We refuse to believe that there are insufficient funds in the great vaults of opportunity of this nation. So we have come to cash this check -- a check that will give us upon demand the riches of freedom and the security of justice.
From "I have a dream", August 28, 1963
Let me leave you with my own joke about gay marriage, which has a lot of truth in it:
I support equal marriage rights for ALL people, including homosexual people. I believe that no matter if you are a straight man or a homosexual man, you have the right to marry a woman. And if you are straight or homosexual woman, you have the right to marry a man. Someone explain to me how that's not equality under the law?
The pedophile may have had an attraction to children from his earliest memory. It seems to him like he was born that way; it is NORMAL-FEELING to him.
But we don't care. We hold adults responsible for what they do with their phenotype.