Just to confirm, it is the passenger's fault for buying tickets at the prices advertised by the airline that they don't deserve to be told that their bags are not going to be arriving with them?
Basically. Yes - Although I wouldn't put it quite the same way, nor "blame" customers per se.
This is the age of low cost air travel. Low cost means that some corners have to be cut, and service compromises have to be made.
Low cost airlines simply cannot afford to have aircraft waiting for hours after their departure time for something like late bags. The knock-on effects would quickly escalate, and then, not only the passengers of this aircraft, but the next plane-load and the next plane-load after that would be delayed and be made late for their holidays.
It occasionally happens that the Captain has to make a decision between waiting for late bags versus missing a slot, going out of crew hours, compensation etc, and all the knock-on effects to subsequent flights and the operational schedule that would cause. Once in a while we reluctantly decide to go without some or all of the bags.
This is low cost flying. One way to keep it low cost was to sell off all the airline's own handling and baggage staff, and employ handling companies instead for lower cost. To make these handling companies low cost, they in turn don't employ very much staff sickness cover. So we are at the mercy of those companies sometimes. We cannot expect old fashioned first class service if we are all paying the lowest fares - the economics just don't work.
If the Captain told passengers that they would be leaving without bags and then passengers wanted to get off, or started arguing, chaos would ensue, and actually, it would not make the situation any better. I think that the airline was very remiss in not telling the passengers not to wait at the destination baggage carousel, but again, they wouldn't necessarily have their own staff on duty at the destination and would have to rely on third party handling companies, who also work at minimum cost and minimum staffing, so messages don't necessarily get through staff are not necessarily available and things don't necessarily happen.
Also, there are sometimes occasions where the hold bags bulk out or are too heavy to carry so cannot all be carried anyway and have to be sent on the next available flight.
Obviously, it is extremely important that any vital medication etc is carried in a cabin bag, not in the hold bag, just in case your bag does not travel on your flight.