Was it? Have you forgotten namespaces and enums?
That's no less a build step than concating, bundling, minifying, etc. When people say "I'm against processing code before deploying it to a web site" but then also say "TypeScript is okay though" or "JSX is okay though," all they're really saying is "I like some build steps but not others." Which is fine! Just say that!
You're not actually suggesting that technology can't evolve are you? Especially one whose original design goals were to process basic forms and are now being used to build full-blown apps?
It's absolutely wild to me that with everything that has happened in the last 2 decades with regard to the web there are still people who refuse to accept that it's changed. We are building far bigger and more complex applications with JavaScript. What would you propose instead?