He has a point let's be honest. In the real world, the only time a landing on water has been attempted by a large airliner was the hijacked Ethiopian B767 that smashed apart on impact. He is correct in saying that hitting water at any speed is very much like hitting concrete. Should my 747 ever find itself gently afloat, then I will put my life jacket on, however 747 flying into a hundred pieces at speed is more likely.
It's also noticeable that cabin crew, like the Police and certain other profession have a "them and us" mentality. The man actually makes a real point in a humourous manner. I always make a point to know where the nearest exit is and where my life jacket is stowed. However I don't have a realistic expectation that I will be delighted that it saves my life. Honestly.
If you want to see "good research" on lifejackets then google the tape of the Ethiopian B767 going in at slow speed into a controlled water landing.......
I can't wait to offload the first smart who's trying to argue himself into trouble
Also, seeking confrontation with those that disagree with you in order to punish them has no place in a grown up workplace.