It's a typical "nanny state" approach to the problem if you ask me. Punish the many for the sins of the few etc.
I agree with what other have said above. Stopping airport bars from selling alcohol in the morning will simply result in people purchasing duty-free alcohol and decanting it into their Ribena / Irn-Bru / Coke bottle instead. People who are clearly inebriated should be prohibited from boarding the aircraft in the first place. Cabin crew need to be less willing to continue serving alcohol to those who are drunk, or knocking them back with a view to getting drunk. The police and the courts need to be more strict in dealing with those who are drunk and disorderly on an aircraft.
I don't see anything wrong with drinking in moderation, at any time of the day, if it suits you. I will happily have a Bloody Mary or a Mimosa / Bucks Fizz / Glass of Champagne when travelling in the morning. Others may prefer a pint or an autumnal spiced mead (Dilly Dilly) but each to their own. Why should the majority of drinkers be penalised simply because of the excesses of the few?