Sometimes a CEO has to give up their entitlement to show that without the customer they are nothing.
And this is what it's all about.
I don't think anyone is saying he didn't have any entitlement to sit there.
But look at it from a passenger point of view...
You've had rubbish service for weeks/months.
You're on a train, and perhaps were not aware there were spare seats elsehwere.
Then you see some sort of "manager" boarding and seemingly keeping people out of the First Class section.
Then spreading out taking two seats to "get some work done".
Why didn't the manager take time to talk to people about the problems?
Yes, it's not perhaps his job but in the interest of being liked, and making customers feel listened to, why not? Now he's become the face and name people will remember, and direct their hatred at.
Did he really have authority to stop people being in FC with STD tickets?
Yes, he's a manager, but I'd suggest that isn't really part of his job. No doubt it would have been "he didn't do anything about it" if it was the other way round though.