Access modifiers don't give you unlimited protection, they help you reason about the code and how it is used. If I change a public method and break something downstream, that's on me and my team. If I change a private method and break someone else's code which was bypassing using reflection or other mechanisms, that's on them.

Languages like Python don't have keywords but enforce using conventions like underscore and 'dunder', the latter of which is actually enforced using obfuscation. It is extremely helpful to signal to users that they should not be using certain methods or fields. When there are no access modifiers available, we still see teams writing methods like "xyx_UNSAFE" or "abc_DO_NOT_USE". It's ridiculous to me to encode this kind of information like this instead of having first class support in the language.

Access modifiers also tell the compiler or JIT what is safe or unsafe to manipulate. It has implications beyond users, and can be a determining factor when inlining or making other optimizations.

This article is so opinionated (edgy?) that it ends with "Inheritance was a hack in the first place." I think, like all things, we need to consider the broader landscape for object oriented programming instead of just saying these things are irrelevant and absurd and useless.