It’s a rule that’s intended to honor – and promote – civilization itself. Correctly applied, in fact, the rule is “Passengers first, women and children at the head of the line”. That is, the crew are supposed to be experienced and professional seamen, who accept the hazards of their duty and recognize that as a rule, passengers are ill-equipped to save themselves on board a stricken vessel, and children least of all. Mothers accompany children, of course, and other females, especially those who may be of child-bearing age, aren’t going to be given an ad hoc pregnancy test, but are going to be among the first saved because honorable men want their own women saved before being saved themselves, and simply apply the rule to “all women”.
It also takes a certain amount of strength and stamina to lower lifeboats by hand from the davits of a ship, especially if they’re being lowered from an upper deck. The process can take awhile, and must be done with some care. The strongest and ablest men should be among the last to leave the ship, presumably because only they will have the strength to lower all of the necessary lifeboats if electric winches fail.
If it was “every man for himself”, then the men would simply evacuate themselves first, and leave the women and children on deck to fend for themselves. This would be an abomination of the worst kind; an honorable man would not assist or permit cowardly men to take the place of women and children waiting to be evacuated.
Obviously “there should be enough lifeboats for all”, but sometimes some get wrecked or the launching davits jam; sometimes the ship lists so badly to one side that the boats on the high side cannot be deployed, and sometimes manpower itself is in short supply to launch the boats. So “women and children first” is just a shorthand way of saying what I’ve just said; it’s instinctive among decent and brave men, and it’s not something to be debated as the ship sinks.
Obviously, this “rule” has been abrogated many times in recent memory. I don’t understand how crew members and officers can live with the shame they must feel after abandoning passengers to their fate before properly assisting them to evacuate.
Women and children first; male passengers next, and then the crew can – and will – save themselves.