You don't limit people based upon some monolithic enemy. The court affirmed the right to liberty and personal autonomy. By fighting the "gay agenda" and everything homosexual you are tramping on the rights of individual taxpaying citizens and relegating them to second class. The amendment which will surely pass now will be the only one I know which restricts people and does not enforce their right to liberty and pursuit of happiness.
You can save the sermon on abortion for someone who needs to hear it. It's not analogous.
As for evil, find another way to fight it than to restrict liberty.
And to the best of my knowledge, it never crossed the minds of a single one of them that the right to "marry" someone of the same sex was a basic attribute of human liberty.
Where did you get the idea that it is?