It's not a JavaScript imitation. This is a JavaScript-like syntax for writing WebAssembly. Other than that, (excepting the closure helper) it's 1-to-1 WebAssembly.
Not everyone enjoys writing verbose S-Expressions [1], even if it makes for a good canonical format.
If you despise JavaScript so much that you can't bear the thought of something that vaguely looks like JavaScript, then don't worry there are other "skins" for writing WebAssembly [2-4] and it should not be too hard to write your own.
Finally, nobody owns WebAssembly. It's for clever people like yourself just as much as it is for dirty JavaScript programmers like me.
[1] https://developer.mozilla.org/en-US/docs/WebAssembly/Text_fo...
[2] https://github.com/tmcw/wah
[3] https://github.com/serprex/luwa
[4] https://medium.com/cirru-project/webassembly-s-expression-an...