Folks, this is the purpose of performance reviews. It doesn't have much to do with your work or ability to do work. It's a bunch of paperwork to justify how management feels about everybody on a personal, not professional level.
No big deal, the meeting was boring, as usual, until a director from another group jokingly commented to our director, my boss, something like, "Gosh, your staff looks like hell. You must be working them to death." It was just a light-hearted, lame joke; got a chuckle in the room. After the meeting, I was pulled into my boss' office where he told me he was sooo embarrassed by the other director's comment. He was really mad. My boss was new to being a director and he felt as the other director was throwing shade on him, implying he doesn't know how to manage a staff, therefore he doesn't deserve to be a director. And everyone in the meeting was laughing, so they all must've agreed. So my boss told me to get rid of the rock-band guy. I rebutted, saying the fact that rock-band guy stayed up all night, and drove straight to work, showed that he was dedicated, and that he (my boss) was such a great director, cultivating a culture of hard work and dedication. My boss wasn't buying, and told me exactly how to manage him out: stop giving him work.
So yeah, it had absolutely nothing to do with his work. It was all because some dude got butt-hurt by a lame comment in a meeting.
> looking like shit in the office is a big no-no
Both of these can be true, for better or worse, but the director is probably also over-reacting. It doesn't seem appropriate to fire somebody over that. Such a director probably has an unhealthy focus on image.