This doesn't really relate to my point. The blog post asked why is it that we can handle games (fancy 3D simulations, sometimes with hundreds of players and millions of objects) at a smooth 60 fps but not scrolling a web page. The parent comment suggested that it's easier to render games smoothly because you know the content in advance. I'm suggesting that software gets optimized (by necessity) until it works well enough. If some website had to display a million elements, the devs would either optimize it until it could do so, or the project would get scrapped.
When I talk about sending 8 KB in a "networked action game", I'm referring to the update packets sent to and from clients in something like Fortnite or Counter-Strike, not a game patch. I'm not trying to make a competition for who uses the least bandwidth (which a 60 GB game would lose just on the initial download). I'm trying to illustrate that games don't run faster than some website because it's inherently easier to make games run fast, but rather that developers, by necessity, optimize games until they run fast (or in this example, until they reduce network lag enough).
I'm not sure why a chat app would tack on something like 7.5 KB of overhead on a chat message, but I wouldn't be surprised if there's a chat app out there that does so. Users won't notice the extra couple milliseconds (especially so because they don't know exactly when the other person hit send). A 3 character Discord message is close to 1 KB including the headers. The same message over UDP in a game might be under 20 bytes, including the UDP header (games could also use TCP for chat - text chat isn't going to strain anything). So I'd say the overhead of a Discord message is still an order of magnitude or two bigger than it could be. Which is perfectly fine; we can afford 1 KB of overhead on a modern connection. It's optimized as much as it needs to be.