These are all distinct topics and should not by synonymised.
close-reasons is for discussing our canonical and custom close reasons.
closed-questions is for raising meta discussions about specific closed questions, and the concept of a closed question in general.
vote-to-close is about a type of vote and its related privileges.
closing-questions is about discussions about the closing process itself.
Closes (and holds) are an important part of how the site functions and has many moving parts. These tags are natural categories that arose to label some of the distinct moving parts of this critical site feature.