How on earth can a poster decide who is likely to be upset by a cutting remark because they are already depressed, as opposed to someone who is feeling emotionally robust and can withstand a bit of sarcasm, ridicule, etc? You can only find out after the event, when - or if - somebody responds by saying "That upset me and I could do without it at the moment because I'm already feeling down".
In the case of jingle, I don't know what she said so can't comment, but why did she feel it necessary to draw attention - in a rather goading fashion - to the fact that she had already had a warning? It was almost like daring Gransnet to ban her.