Certainly, a "kiss goodnight" or any other activity taking place at or around midnight is not intended for a 4.5 yo.
However, at this point in
DCL's existence, I believe there are a lot more guests on the ships traveling without young children than there were 10-15 years ago. You have tons of families now who began cruising regularly or semi-regularly with DCL when their kids were young some 10, 15, 20 years ago. And now that the children are older - adults, in many cases - these families continue to cruise with DCL...with and/or without the adult children (our 23 & 20 yo still love sailing DCL). This demographic - which I believe grows every year on DCL - could, and should, be better served with some activities that extend through midnight-1am.