Wandering Vag seems to have had a crew, so leaving all the gates open, however annoyed he'd been by the people behind, just seems an expression of egotistical and deliberate obstructionism, as well, in fact, of giving a thoroughly bad example to the boat behind, who, having learnt from him, may well never close a gate behind them again. All in all, a totally unnecessary and stupid bit of unpleasantness, deliberately designed to spoil someone else's day,and almost certain to be counterproductive in the long run.
What commercial boats did a hundred years ago is irrelevant. These days, due to lack of maintenance, leaks, low water levels etc, we need to shut lock gates. He's just taught some inexperienced person the opposite. Clot.