It doesn't say that it's good for someone in the hospital to spend all of their time complaining about their situation, it says that their co-worker who is visiting to be supportive probably shouldn't bring up how it was hard for them to do it.
I think GP has valid points about this “rules” impact.
Basically everything in there has exceptions: sometimes the compassionate thing to do would be to give someone in an inner ring advice. Just, 9/10 out of times, advice offered is unhelpful and worsens things. Obviously it's not okay for the person in the middle to say "anything", either.
But, it's a really worthwhile thing to consider. Is the person you're going to talk to closer to the trauma than you? If so, would what you're saying be better to say to someone further away, instead?
Indeed. But if I were in some acute treatment in USA, in the center ring, I probably feel an unrestrained urge to ask for financial advice. "Dear, can the kids be indented into slavery if I die without paying the bills? Yes? Because I signed that form? Oh...somebody should have given me some advice..."