I didn’t remove the participants’ section. If you are thinking about doing so, give it a chance, as with other Discourse features; the Devs have put some thought into it. It shows all participants even after only 5 of 15 posts are imported. (changeable setting) Also, the imported responses exclude posts by level 0 forum members. Which I find helpful.
In short, over time, I’ve noticed that it’s not all the time the participants’ list and the imported comments will be identical. In many cases, it helps to provide the blog reader a more accurate view of the level of comment activity without having to import every single post or risk importing posts from the first sign-up members. (which I believe can be changed in settings as well)