Apparently Mormonism is never supposed to evolve as a religion. It's hard to tell if he means religious laws or civil laws here, a dangerous ambiguity. The goal is to discourage people from engaging in homosexual practices in the first place, and when they nevertheless proceed in their homosexual behavior, to encourage them to do so discreetly, so as not to shake the confidence of the community in the polity's ability to provide rules for safe, stable, dependable marriage and family relationships. Knowledge of your existence might shake our fragile world. It sounds once again like he has no faith in the strength of his own religion and community to survive challenges and accept differences.
Card really seems to have swallowed the religious party line hook, line and sinker.
In most of the USA, you can be fired from your job, thrown out of your apartment, refused entrance to your lover's hospital room, thrown out of the military, and have your children taken away from you, all for being homosexual. And let's not forget the suicide statistics and violence against homosexuals. Card raises the point that labelling someone a homophobe is used to silence them. When you move beyond tolerance to advocating the suppression of a group, no matter whether the motivation is religious, moral, or personal , that's evidence of a phobia. This is the fundamental point.