I've always wanted to be able to tell people they're the bottleneck. I've had talks with management about this. "We need to tell people bluntly so they understand the impact they're having."
Nope, it could hurt a relationship and relationship is more important than delivering.
I don't want to be an ass, but I do love this approach by Mr. Beast.
That said I feel like having people who are constructively blunt in your organization can make all the difference. If you listen to stories about successful managers and CEOs it often comes down to bluntness.
It can also go the other way though. Being blunt while lacking in other areas (technical knowledge, judgment, vision, ethics) will just add toxicity.