You absolutely don't have to have a concrete, well-constructed opinion on everything, or even really anything, but if you plan to spread an opinion you have about something, you should make sure it's concrete and well-constructed first.
Sure, but do realise sometimes not having an opinion is a very privileged position to be in. There are others who are forced to have an opinion, or are currently being forced to live someone else's opinion.
I strongly believe the internet forgets that and mandates everyone to have a position on anything and everything, regardless on how well-informed one is.
I mean it was understandable— everyone praises the five good emperors for choosing successors but none of them actually had biological kids, and there was no precedent that the successor would be chosen. Realistically, Aurelius wanted to avoid a civil war and wasn't like entirely throwing, I think I saw like a story about how he like. Didn't want to do it but it was like the only good outcome or optimal at least
Commodus doesn't appear to have descended into megalomania until a few years into his sole rule. One expects the power got to his head rather than him simply being born wrong. C'est la vie!
My brother in Christ, it is literally impossible to have a fully formed opinion on every single topic. You're allowed to not care about things you don't care about.