I can see how that would be, as it could expose a lot of the hidden groups that exist on the platform and maybe for other reasons as well.
I can also see how the opposite—not letting people know which groups have access to a certain category—could be considered a violation of privacy. For example, if I post to the Contribute > Feature category, if I know it’s “restricted,” that could mean only other people in a Feature group could see it or it could mean everyone on the platform could still see it but maybe one group just doesn’t have the ability to create topics or replies. For a mostly public forum like Meta, maybe not a huge deal, as we probably assume most of the things we post are public, but as I think about hosting more private conversations, I become more sensitive to “wait, exactly who is going to be able to see what I type?”
Regardless, thank you for letting me know that it’s not currently possible but could be with a plugin 