While this is only my experience, when I write job requirements that cover multiple languages or frameworks it really is 'any of these are fine'. The theory is that you don't want to filter out people that would otherwise be a good fit - because for the most part smart people can learn new frameworks and languages pretty quickly. You are correct that it is suboptimal for people wanting to work on a specific tech stack, but if you're not getting any applicants because your requirements are unnecessarily strict it's not in anyone's interest.