Please reconsider your tone. It sounds like you were disappointed that you didn’t get to show off something you know, so you chose to insult someone else instead.
The site would be better without such comments. This might make you feel better but it’s just noise that hundreds of people have to skip over.
Post's author is a member of Jetbrains Kotlin team. I wouldn't say he has no idea what language designers are thinking about since he's one of them.