Well, of course, if you’re using transpiled languages, you’re generating JS code, but you seldom need to deal directly with the JS output. In the same way, when you compile C++ to assembler, you’re generating a lot of machine-level code. It doesn’t matter, though, unless you need to look under the hood.
(Until recently, CoffeeScript forced you to deal directly with the JS output. CoffeeScript was a poor execution of the idea of transpiling.)
You’re quite right, people write horrible code in every language. The problem with JS is that the language makes it so easy to write bad code. It almost encourages sloppy coding.
I’m not sure I agree with you about education/training/mentorship. There are plenty of books and online resources and training courses available for JS. Probably more so than for any other language. Although it’s quite possible that we have bad teachers teaching bad practices to millions around the world. Eric Elliott wrote a good article about this some while back.