"Fun Fact: thing that every single person reading the comment already knows, perhaps even something explicitly stated in the video or overwhelmingly apparent"
"I like how/Can we talk about how describes the complete events and point of the video."
I mean the notions in the comments themselves are fine but those words preceding it changes the meaning for me into this, like, foolishly authoritative statement? Fun Fact implies someone believes they're sharing exclusive information they have that very few other people are privy to. Yes, I know Toby Fox made Undertale and worked on Homestuck as well. Everybody on the internet knows that. Fun Fact: when you breathe air goes into your lungs.
The "I like how/Can we talk about how" gives an impression that someone is going to share their unique perspective, something they have noticed that they feel needs to be heard by others, so that they might notice it too. So it's kind of annoying if, say, under a clip from Seinfeld someone comments "I like how--" and then describes the joke in the scene. Like, oh, you liked... the video? that's cool. I think there's a less roundabout way you could have said "I liked watching this video." I don't know man. I'm overthinking this way too much they're harmless comments I'm just tired and still awake at 3:45 AM for someone reason someone come knock me out.