OK, to put it back on topic, of course there is no need to be rude to a passenger (and the other way around, I hasten to add). But I can't comment on what happened, I wasn't there, and what one person sees as humour, another sees as rude. Perhaps the crew member didn't deliver the punchline very well, but it's a well known thing to say to someone who pays no attention to the demo, I've heard it before.

I should add, that as a passenger on the MAN-LHR shuttle a couple of years ago, the guy in the seat across the aisle was TALKING ON HIS PHONE THROUGHOUT THE DEMO! The crew member was about three rows in front, and he yacked on the phone from start to finish. He was obese and had the seat belt dangling, and the crew member didn't even pick him up on that either. Perhaps she was scared of the abuse she'd have to listen to if she mentioned it. I imagine he would have needed an extension seat belt. I'd like to tell you where I was tempted to tell him to shove his phone, but I'm too much of a lady.