As you say, almost everything in interpersonal skills is a form of communication.
This is a meta tag. If you're asking a question about a specific form of communication, that tag is preferable (e.g. emails, texting).
If this post gets support, the mods can request the CMs blacklist the tag to prevent it being recreated. This is better done before the tag gets too unwieldy.
Right now it's used on 45 questions and the only question it's the sole tag on is closed. This means that it should be pretty easy to review the questions with the tag currently and, if necessary, replace the tag with something more specific. This tag is regularly used with conversations, which should be an acceptable replacement for in-person communication in the way email and texts are for written communication.