Is this SOP?
If it is a standard operating procedure, and you flew more than one sector with them, did they do the same thing on the other sector as well? Have you ever flown them before or since and was it repeated? I can’t think of any reason to command the passengers to put the blankets and pillows between their backs and the seatbacks. That sounds very strange to me.
Never hesitate to ask the crew a question about your flight. You may not get the answer you want, but it is certainly within your rights to question us. I would suggest writing the company about your experience, just as you did here on PPRuNe.