Clarity of syntax is a matter of opinion (personally, I agree that Python is clearer than JS... Java, not so much.)

Implying that JavaScript can't "run at a useful speed" is wrong, using modern implementations. This is especially true for code that runs through lots of repetition as the just-in-time compilers in the JS engines do a remarkable job.

Not to mention that viewing JS as a UI-oriented language seems a bit out of date given the 40k or so packages for Node.js that are in npm.

JavaScript of today is pretty different than JS of 2007, and there are more changes coming with generators, iterators, destructuring, class syntax, arrow functions, promises, etc.