Sure, the code camps are selling snake oil by and large. But re languages, you need to bear in mind it’s fairly irrelevant which language a person knows - if someone knows JS very well, they can transfer that knowledge to whatever language the company uses. Having a perfect fit gives an advantage for a few months, but after that they’re likely to be up to speed. The more languages (particulaly in different paradigms) a person knows, the more attractive they will likely be (JS + an OO language + SQL is a fairly useful combo, a functional language adds to that, then eg someone who knows a language like Haskell or Erlang iin addition s going attractive because it indicates things about the programmer)
Job posting are (if the recruitment person is not just copy pasting crap) just saying “ideally, it would be nice if a potential hire knows these things” - someone who knows loads of tech on the job posting laundry list will get an interview, sure, and will likely be first in line if they seem ok to work with, but that almost never happens (ie you take the main technology as the baseline - JS, PHP, whatever, if canidates have those skills, cool, if not go to something similar, hire from that, or if they have some interesting combo, interview).
TL/DR the job spec is just a nice to have, weeds out some potentially bad candidates (puts off some potentially good ones as well), the interview is just a business negotiation: can you make the company money/are you a useful reason to spend company money.