Commodus did plenty as a child, even if it was overshadowed by later lunacy. My argument was poorly made though. I'll try to restate:

It's easy to get swept up in Meditations, viewing Marcus as the stoic Philosopher King that has profound lessons for us even today.

Parent tried to remind everyone about Commodus, and in my opinion correctly so; if Marcus lived up to the myth surrounding him, he'd have intuited the situation and dealt with it.

But he either didn't see what was coming, or decided to do nothing. Because for all the hype, he was just a man. Keeping this in mind is an antidote to getting carried away by what is a genuinely compelling piece of writing.

I wouldn't make this argument in a vacuum, but I saw OP get downvoted and wanted to jump in because I thought it was a fair enough point.

So if he was as great as people say he was, then he would have intuited the fact that his son would eventually turn out to be a bad emperor, and would have murdered him? Hmmm...

Yes, that is my argument.

I don't think most people would consider inability to predict events that will occur after your death, and the act of not committing filicide to be very serious character shortcomings.

Commodus renounced Stoicism after his fathers death, and didn't do any of the terrible things he was known for until after then either.

This argument is beyond weak in terms of criticising Stoicism or Marcus.

There's a big difference between using Commodus as proof of Marcus' flaws, and using him as proof that Marcus was only human.

If the argument were that weak, you wouldn't bother with the strawman to counter it.