There's nothing preventing you from writing analogous data structures in any language.
No one wants to admit that their language choice is because of the cultural norms in their language community, but if you can hide some complexity behind a language construct, you can hide the same complexity behind a function call. It's just a question of how much of the work required to do that has already been done by the community.
You're just not going to win the "my language can do x more concisely than a function called x in your language!" argument. You're better off with "this is easy and my language and you'd have to write a function to do it in yours."
There's nothing preventing you from writing analogous data structures in any language.
The problem is the language culture and what is idiomatic. I write Python in my day job and while I could certainly write immutable data structures in Python and code in a way that treats data as immutable, it would be going against what is idiomatic in the language, which means that it won't play well with libraries and that my coworkers can still trample over my data without my knowledge. That is, the language gives me no guarantees whatsoever that my immutability is actually respected and that other code somewhere else that I did not write (either application code written by a coworker or library code written by a stranger) respects the immutability.
I find this argument similar to asking why bother writing in any high level language when you can implement the same things in assmembly. Hell, why don't we all just program turing machines directly?
Languages carry a lot more with them than just the features - they carry idioms and culture and community trends. All of these (and even small syntax differences) influence how we think about problems and how we create and structure solutions. They also influence how my code will interact with other peoples (and theirs with mine).
You're right, _you_ can write immutable data structures in any language. But for example, immutable.js and/or mori do practically nothing to fix the mutability problems with javascript, since immutability is not the default.
No one wants to admit that their language choice is because of the cultural norms in their language community, but if you can hide some complexity behind a language construct, you can hide the same complexity behind a function call. It's just a question of how much of the work required to do that has already been done by the community.
You're just not going to win the "my language can do x more concisely than a function called x in your language!" argument. You're better off with "this is easy and my language and you'd have to write a function to do it in yours."