The airlines introduced this ruling as a result of security concerns and security regulations! You are not allowed to bring sharp objects through security......PERIOD. If some security checks don't locate them, or some airlines are lax and don't attempt to enforce it, that is not reason to abuse those airlines and crews that do. BA even bans metal cutlery- people have to eat steaks with plastic tools.
IF you are diabetic, all you have to do is get a Doctor's Letter to carry needles! For goodness sake, it's not picking on diabetics, it's not for nothing, it's not crews being brutal- it's regulations! Are we going to have another 35 page thread talking this to complete and utter boredom? Get a Bloody Note!