Humanism is a religion. Advocacy of homosexual conduct is in many ways a religion. Earth worship, radical environmentalism, one-worldism, all of these are forms of religious faith. They are belief systems which are coherent and comprehensive. People have a right to those opinions, but they don't have a right to require us to subsidize them with our taxes.
Some people mistakenly believe that there is such a thing as neutrality.
There is no such thing. Positing that the world was created impersonally by random chance is a religious view. The very notion that it is okay for the President of the United States to commit adultery represents a religious view, which is antithetical to the Christian view. There is no such thing as neutrality. All views are inevitably and inescapably religious.