It's easy to criticize, because it was a bullshit response by both the airline staff and the security staff.
They needed the seats to move their staff operationally. To do that, they needed some passengers to volunteer to not fly. To do so, they needed to offer incentives, not demands.
The airline's problem is that they didn't want to pay enough. So they used force, not only that, they used public security (police) to enforce a private contractual matter (not providing travel, even though the passenger was in complete contractual compliance).
The security staff were briefed, and if not, should have waited until they were. He wasn't "acting strange", he was upset at not travelling as he had paid for, and wasn't been offered a reasonable alternative.
Excusing this behavior is allowing it to continue.