This is what it's like making jokes on the internet in general these days. Say something that is clearly absurd for the sake of humor, and then get hit with a ton of "um achtually..." responses.
That's not what happened in the scenario above, is it?
Asking 'why aren't koalas considered bears?' isn't clearly absurd.
If they'd said the punchline and then the other person said well actually they're marcupials, then fair enough. That just isn't what happened here though.
Sometimes it's so obvious that I wonder if the person knew it was a joke and decided to troll anyways. Other times I have to remember that it does take experience to recognize it, and some people have additional limitations like not speaking the language
Like if I never played a video game, I might not recognize the very obvious wall with a different texture that I'm meant to bash through