I would say that it's more akin to being told as a parent that your children are morons. Your children may be ignorant to this "greater truth," but that doesn't mean that you won't be offended as a parent by having your children being presented as dumb, ignorant clods.
That's an interesting way to look at it. I see where you're coming from.
But then let me ask this question... so some rando has already called your kid a moron. What are you going to do about it?
Because the game and the people involved have already done that. And no amount of questioning it is changing the fact that they've already called your kid a moron. What's your next step here? Even if you somehow can get one or two people to recant and say "Naw, I was just kidding!", there are going to be thousands of other people saying "No, you were right the first time." What do you do then?
Seems to me, the only thing you CAN do is to just not give what they say any credence. So some rando says your kid's a moron. So what? You just stop talking to that person or caring what that idiot has to say. You concern yourself with your kid and only your kid... and you let other people blow whatever smoke they feel like blowing. You don't let them take up residence in your brain... because once you do that you NEVER get any peace of mind.
What's done is done. All you can do is just not care that it was. Because goodness knows nobody else cares that you seem to.