I'm going to back the OP here because I actually saw similar on a BA flight from CPH-LHR last week.

Passengers were instructed to not put coats in the overhead lockers until after all bags had been put up and then 'if there was space' they could put coats up afterwards. Coats that had been placed up already (before the announcement was made) were removed and passed back to their owners by cabin crew. It wasn't done in the rude way the OP experienced but if it had been my coat that was summarily dismissed from the locker I would have been displeased. One poor chap had his suit jacket pulled out and the contents of the pockets spilled all over the floor.

As an aside, I've had too many suits jackets/coats ruined by oil and grease in the overhead lockers that I don't put my coat up as a matter of course now.