That’s not the worst argument in the world. “People shouldn’t act on same-sex attraction because...” is closer to the central archetype of hate speech than “People shouldn’t drive SUVs because...” is. And the full argument is probably something like “Arguing against homosexuality is hate speech, and therefore harms homosexuals.” — which is a sloppy argument, but a cleaned-up version would be “Arguing against homosexuality encourages people (through the magic of virtue ethics) to view homosexuals as vicious. And it legitimizes (through the affect heuristic) the established pattern of homophobia. Therefore, you should not argue against homosexuality. By the way, hate speech shares these features.”
That’s not the worst argument in the world. “People shouldn’t act on same-sex attraction because...” is closer to the central archetype of hate speech than “People shouldn’t drive SUVs because...” is. And the full argument is probably something like “Arguing against homosexuality is hate speech, and therefore harms homosexuals.” — which is a sloppy argument, but a cleaned-up version would be “Arguing against homosexuality encourages people (through the magic of virtue ethics) to view homosexuals as vicious. And it legitimizes (through the affect heuristic) the established pattern of homophobia. Therefore, you should not argue against homosexuality. By the way, hate speech shares these features.”