A disputable statement. The key words are "As long as they're not harming anyone else". Yes, I'm inclined to agree. But what is "to harm someone"? Physically? Or morally, too?
If someone prefers walking naked, is he harming anyone else? Why does the government put restricitions on this kind of behavior?
Does saying to a child "Oh, boy! You know, being a gay is so cool! There is nothing abnormal in it. Two men can love each other, live together and make a family. Why not to try? The traditional family is outdated" harm the child's psychology?