In DM(Design Manager), whether non review author/participants can add review comments?

Hi

In DM product, review creation feature is provided.
When creating a review, should also configure participants and resources info.
Once review starts, participants would perform assigned tasks before the review being finalized.

I found other users who is actually not included as review author nor any role of participants could still add review comments.
I want to check whether this is normal or it's an issue?

If it's a designed behavior, any user in the project area could freely add review comments, what's the point to add participants information to the review?

Thanks and Regards