Yep. WebAssembly today is literally just a better/faster asm.js.
The argument against it linked above is nonsense. Most arguments like this that I see tend to fall into one of these boxes:
1. Using wasm as springboard to argue against something else they don't like.
— e.g. disliking closed source code / source obfuscation / minification is a fair position, but it's not helpful to anyone to pretend that wasm introduces anything different here (as has been pointed out, wast's inclusion of type information actually makes it slightly more readable than minified JS).
2. Arguing against something that wasm could maybe one day become.
— Right now wasm doesn't enable anything you can't already do with asm.js, so the idea that it somehow kills JavaScript or whatever is wrong; anything that can compile to wasm can compile to asm.js. Sure, maybe one day wasm will gain DOM/GC/etc. functionality, but asm.js could just as easily gain a lot of the same proposed features. (And wasm/asm.js aside, plenty of languages already compile to JS quite successfully; this hypothetical future wasm would just make them faster.)
3. Seeming to have only a vague sense of what wasm actually is. I think arguments like #1 and #2 have led to a set of talking points that don't at all reflect reality but sound correct to developers who don't have direct experience with asm.js/wasm.
— e.g. the argument from the linked Lobsters comment that "It solves problems that we don’t have. ... If performance is the important thing you pull on your big kid pants and write C/C++/D/Rust and if ... performance isn’t important, you just write in JS." neatly summarises exactly the point of wasm while somehow trying to frame it as an argument against it.