JavaScript is popular because the learning curve is low and it was good enough for the web. Otherwise it is pretty mediocre even when just compared to scripting languages.
Then, the "about" page of that blog is very concerning: "I am a world-class software developer". A world-class software developer would be people like John Carmack, Linus Torvalds or Dennis Ritchie.
That's a weird criticism. Object-oriented programmers are premised on mutation. As for JavaScript itself, mutations can be avoided. 'const' to prevent reassignment, using Object.freeze, or just applying functional programming principles and keeping functions pure.
I'm a Java OOP developer, and I make everything I can immutable. It's a design decision adopted by most of my colleagues.
2) Mutate the prototype of a "frozen" object and you would indirectly affect it through its prototype chain... or mutate an nested property inside a "frozen" object.
Most of JS standard library and most popular frameworks and libraries have fully mutable definitions. That sucks and is BAD design decision.
This counterargument is not a good one. Just because other languages do things a certain way doesn't mean it's the right way in every situation. C++ has multiple inheritances and template metaprogramming, but that's C++.
> Most of JS standard library and most popular frameworks and libraries have fully mutable definitions. That sucks and is BAD design decision.
It's subjective whether this is a bad design decision. For the standard library, this enables polyfills. As for the popular libraries / frameworks, they have the option of freezing the prototype. They don't do this because they make the fair assumption that the client is not mutating the library state. It's the programmer's fault for breaking the interface contract and mutating the implementation. At any rate, this would be a criticism of the ecosystem, rather than language. If the criticism is about untrusted third party code, it's not an apples-to-apples comparison between JavaScript and other languages that are operating in different environments.
2) Just like you can polyfill your code, malicious input can poison your prototypes.