Irene, I honestly don't think that any of the members who replied to you were guilty of anything worse than a natural, emotional response based on protectiveness towards those with long-term illness and their carers, and I did not see anything that a moderator should have edited or deleted. My own caveats were based on my feeling that the situation was not quite as simple as it appeared, and my natural tendency to analyse and react intellectually rather than emotionally.
One of the problems about communicating in writing (as I think someone has already mentioned here) is that nuances of tone and expression are lost, and a text may give a false impression. (This is part of the reason for the common use of emoticons in internet discussion groups, to try to substitute for the facial and vocal subtleties that are lost). On a highly emotional subject such as this one, there are always dangers of misunderstandings. I have sometimes been accused of sounding 'cold' or 'haughty' on internet forums, usually by Americans much younger than myself: my slightly formal, slightly old-fashioned, British prose can apparently give that impression when read by a young American. Your first post, and indeed at least one of the later ones, did sound unsympathetic and exasperated, even though they may not have been intended that way.
Am I right in suspecting that there is already a 'history' involving the group and the gentleman with the sick wife, involving matters that were nothing to do with her? If so, I doubt whether this is the right time or the appropriate context in which to bring your concerns into the open. Both the poor lady herself and her husband are too vulnerable, and with hindsight, you would probably deeply regret taking what amounts to punitive action. Imagine how you would feel if you effectively chased him out of the group, and a couple of weeks later, his wife died.
Having said that, I think that some of the issues you have raised are valid and interesting. The wider social lives of carers, dementia sufferers and those with whom they come in contact are full of challenges, pitfalls and potential hurt feelings.
Tristesa