It was not an insult, it was an observation. You're pretending that actions can be considered in isolation from motivations. Kids can get away with that kind of reasoning because they lack context. Grown-ups don't get that sort of free pass.
To your point: I do not need to consider the basis for the actions of thief to know that they are wrong or that the perpetrator should sanctioned for such.
We're not talking about theft. And even then, we can and often do make distinctions about theft based on the motives of the perpetrator. For example, the person who steals because he's starving, is in a different moral class from the person who steals because he likes to steal. Stupid kids who steal are different from career criminals, and are treated differently.
If it can be said of homosexual behavior that there is a negative impact upon individuals and society from these actions, then the same logic applies.
Here again, you are operating without context. I know homosexuals, both male and female, who are profoundly useful members of society; who are pretty private about their activities; and who don't spend a lot of time pushing their agenda on others. Aside from your attitude their behavior, what would make those particular folks "bad" for society?
It's not as simple as you would have it be.