So what? A lot of people are also complaining that it resembles the JVM. Do you think that historical mainframe bytecodes would have been a good match for web applications?
I don't know, I know nothing about mainframes. I do not understand if your criticism is that they are making mistakes that have already been solved half a century ago (which is a good criticism, if true) or that they are not giving proper recognition.
The new shiny thing about WASM is that it fits into the constraints of the web platform. I suspect that even the best mainframes bytcodes had at least slightly different constraints.
I would really like a discussion and a comparison of them, seriously, I would read any such article I could find as the topic is interesting. But comments like this feels a lot like a hipster hating on the mainstream.