Mind you, I haven't had the misfortune to be randomly selected for a bruising eviction.
Perhaps these things happened all the time in the pre-social media age. Today, with a legion of smartphones poised to preserve any moment of poor customer relations, this was always going to go global. The airline's disastrous PR response amplified the awfulness. They could have front-footed it, worn their share of responsibility and perhaps even cheekily said they too were shocked by the airport security team's over-reaction.
Pass a bit of the buck to the airport.
The handling of the PR was one disaster, but the selection process itself is awful. Instead of dragging some poor screaming customer off the plane, how about we find a calmer, more rational way to select the passenger who will be compulsorily ejected?
Over-sold flights are common in the US - I've often found myself at the boarding gate and heard the gate agent ask for volunteers (pretty well paid, too - they were offering $1150 to anyone willing to give up their seat on the United flight last week) to miss the flight.
Here's the answer. When passengers are all checked in and the airline knows the flight will be overfilled, weigh all the carry-on bags of passengers as they get on the plane.
Those with the heaviest bags at that point are the first to be evicted.
Random selection seems unfair - even if, as United bluntly put it, they had the legal right to do so.
By basing the eviction routine on the weight of passenger's carry-on luggage, the airlines would be turfing someone who's actually breaching the rules by bringing on a bag that weighs more than 7kg. Straight away, the airline would have the moral high ground.