Haters are going to hate. It doesn't matter what field/discipline you're in. JavaScript is as much a proper programming language as Python or Ruby or Lua. They're all high level scripting languages that do roughly the same things. Only one of them is natively in every browser (JavaScript). JavaScript turns out to be fairly forgiving (you can intentionally or unintentionally leave out semicolons and it will generally still run as intended).

I wouldn't worry about "technical elitists". It's really the Dunning-Kruger effect at play more than anything. The less someone knows, the more they think they know, and the more likely they are to be outspoken about people they think are "below" them. There's also a fair amount of disdain between people in different programming paradigms (OO vs Functional, Low-level vs High-level languages, etc). NONE of that matters though. Build cool stuff and keep getting better. Let the "technical elitists" spend all their time worrying about what is or is not proper programming while you get on with your life, build cool stuff and continue to get better.

It's a lot different these days where so much is on the web and undeniably Javascript-driven. While there are always going to be purists who refuse to recognize Javascript as anything more than a dinky toy, their opinions aren't exactly relevant or prevalent anymore.

I suspect Khan Academies decision was more motivated by implantation details. It is far easier to right an interperater when you can ask the browser to interpetat for you.