People who thrive on ridiculing others would have a hay-day if someone revealed that weakness to them. Those kind of people would start out tip-toeing around the person in mock support, but continue the backstabbing and ridicule when the person isn't around. A sensitive person can pick up their non-sincere actions which feels even worse. Soon they'll loosen up and be right back at it again in full earshot of the person, with yet more ammunition for ridicule... making fun of him/her for being "too sensitive" or "not having a sense of humor."