Nobody deserves to be degraded or humiliated for the job they do, you've obviously never been in a position where people work for you or under your management.
Peterpuffer
While we don't deserve a lot of things that happen, they still do. Keep in mind that this thread is about some jack ass writing that the waitress should go on a diet. That's an insulting, unpleasant, unkind and irrelevant thing to put on a comment card. Does it mean that, said waitress or her co-workers should retaliate? I don't think so.
These days and being retired, I am most often the customer. I can assure you there is no way I would ever say such a thing about someone on a comment card. In fact my wife and I make it a point to compliment wait staff for all their good service. We are well received wherever we go, especially those places where we are repeat customers. Just this morning at breakfast, our server sat with us and chatted for a few minutes. This is very often the case when we go out to eat at a place where the staff knows us. We also tip well.
The above being said. I still maintain that it is not good business for a server to refuse service or address negative comments such as the one exampled in this thread. If I were the manager at that facility, I would support that waitress not waiting on that customer. I would not support her or her coworkers telling the customer off.
Some people can be incredibly rude to service industry workers. It is wrong. Chances are these customers are doing this just to bolster their own egos. Smart people know this and will in most cases just blow it off.