There have been a few posts mentioning the change in the US since 9/11. Well you can stop looking at the past through rose-coloured glasses - America's descent into authoritarianism had started well before then.
I went to Hawaii with my wife for a holiday in the early 1980's, and I was shocked at the aggressive attitude of the immigration officials. I'm Australian - you know, the country that said "All the way with LBJ", sent troops to Viet Nam, and subsequently to Afghanistan an Iraq. I vowed then never to go back. And it's even worse now:
Mem Fox, Australian author, gets apology after being wrongfully detained at LA airport - Donald Trump's America - ABC News (Australian Broadcasting Corporation)
And I the ineptitude of the UA staff is just breathtaking. By contrast, I remember a Qantas domestic flight a few years ago, where a minor incident was handled very cleverly by experienced and professional CC. An economy class passenger had popped his oversized carry-on suitcase into a Business class overhead locker on his way down to the back of the plane. The steward (with a grin on his face) announced that there was an unidentified bag on the plane, and that in accordance with airline regulations it would taken off unless claimed. Embarassed passenger came up from the back of the plane to collect it. Job done, no drama.
I'm not for one second condoning bad behaviour under any circumstances. But, when you treat paying passengers like why are you surprised when some of them act badly?