Yes. That's the joke.

Why did people downvote this person? No, really, why? Like, this isn't the worst example of this I've seen by a long shot, but I guess I'm just not in the mood for this crap right now.

1. Can you even tell if the implication was that they didn't know? Or was it maybe instead that they were being snarky?
2. If they genuinely didn't know, are they bad for it? I mean, you're downvoting them because you dislike their statement, right? It's not over irrelevancy. But you're born knowing literally nothing, so what is "common sense", and at what age does it happen? Is it a crime to be unsure of something? And think about it— do you really want to be the kind of person who is a dick to random people just for lacking a bit of sureness/clarity/awareness?

Ugh, social media is a great way for people to discover that they share ideas and tastes with other people, and therefore validate their own humanity; but it's also a great way for them to get bullied by dumb mobs who don't know them, into insecurity and mental health issues.

Eff off, internet.