I wonder how those responding on mumsnet would react travelling on many medium & long distance flights that offer a wide variety of video entertainment on their flights? Whilst someone using a personal device could turn it slightly to prevent a child next to them seeing the content, on a plane the screen (in economy at least) would be build into the seat in front.
Each airline and/or their InFlight Entertainment provider has a strict set of rules regarding content. ElAl (Israeli Airlines) are known as having about the most stringent rules about what can and can't be shown. Singapore is fairly strict on certain themes, as is Garuda. The need for policy goes back to when airlines first began to offer 'Mainscreen' projected and then overhead entertainment. It's why 'Mr Bean' films were, for years, some of the most popular IFE content.
With the exception of things like 'Mr Bean,' almost all airline IFE films have always edited to a greater or lesser extent, precisely to avoid causing issues. It doesn't matter that it may still show its BBFC (or other) rating - it won't be the same as watching at the cinema. Some airline edits are up to about 15% shorter than the cinema version.
Now that seat back and individual screens are prevalent, some of the editing policies have been relaxed on certain carriers, but the seat back and individual screens also feature lenticular filters, which means that they can generally only be viewed in direct line-of-sight.
Filtering and dimming is also used as screens, particularly with moving images and 'flashes' are highly-disruptive on night flights when the house lights are down and passengers wish to rest.
So, there's far less likely to be a reaction to IFE on an aircraft, precisely because it's controlled.
Personally, I see less in this about the professionally-offended, and more (potentially) about the increasing numbers of people who seem to behave in public as if they're in a private bubble, with either no awareness of or no care for how their behaviour affects others - from earphoned zombies to the guy watching porn in the British Airways Lounge at Copenhagen last time I was there.