Honestly as someone (on the team) hiring for a job where someone else wrote the job posting, ignore the number. Just read that as "do you think you enjoy maintaining a codebase written in X".
Yes but with time you gain experience in one or more languages and you can choose a job with the ones you like (or tolerate more). You don't need to pick or specialize one to apply for this kind of postings.
They don't enforce the number of years, but they could ask you quite deep questions about the language.
Even if you're a senior Python/Javascript developer, with experience in C# in the past, etc., if they start grilling you about Ruby, you probably won't prove that you're as equally productive as a similarly smart dev that is an actual senior Ruby dev.
Job postings are the fucking worst.