I wonder if this is why I’ll see a post has a larger comment count than the comments I can read, too.
If you've blocked someone, that person's comments and all comments replying to theirs are hidden from your view. This is my only guess why you might be seeing this. The comment count you see on your instance should be accurate, since it only counts comments it knows about and it doesn't know about defederated ones.
Yeah, this is consistent with my experience too. I got one or two participation ribbons in my whole school life (graduated early 2000s), but they weren't common, and they never came at the exclusion of winners being recognized.