I think an option to only show comments from people subscribed to the same communities as you, or the community you're viewing the content from could solve this.
I'm not saying it couldn't work but I don't think it would be as trivial as that.
I also like that subreddits were able to foster their own communities with different expectations and cultures. I feel like using tags you are more or less forced to have a single overall community vs many smaller ones.
The first is an account setting for the user that allows them to hide all comments from people that arent part of any community that the post shows up in: https://github.com/kraftman/TenTags.io/blob/bc6f3046dda4815b...
The second is to allow filtering all of the comments by the communities the comments came from: https://github.com/kraftman/TenTags.io/blob/dev/api-cdn/view...