Spot on. In short doesn’t matter who you are or who you work for it is possible for anyone to have a bad day.
What does make a difference however is company ethos, culture, and core mission statement...and how rigorously they promote it.
Delta, and my son works for them, has a very strong commitment to customer service and company loyalty, and I have in my dealings with them generally found them to be very good, They work along a co-operative mentality and profit sharing where everyone gets to feel that the better the team/family/airline does the better they personally do.
I have for many years felt BA was the tops, though in the last few years that does seem to have slipped a bit with the cabin crew strikes and recent management decisions which seem to have eroded customer confidence in the quality of the service.
One certainly does not expect to be assaulted while travelling with a company though.