Which is bizarre as while he states it is his current understanding, who the heck is educating him and pointing out the historical data is from well over four centuries ago to his timeline. As with Tom Paris and others, being fixated on solely the mid-20th century has a few drawbacks (just what is it with the 1960s, did they all attend a party and someone spiked the drinks?) A minor script polishing would take care of anything while being true to Roddenberry's idealizing combined with showing things from 24th century perspective since nobody in the cabin gaffed or chortled at what happened in the past since their whole civilization had moved on (hence the progressiveism you allude to?) Or 1980s' idea of what being progressive is is a lot different. Meaning nobody would chortle, but a softer segue between characters, keeping in mind it is Dr Pulaski who gets the line about how human society strayed from that form of family structure. So it was progressive and trying to be true to the time and place the crew were on (24th century with human Pulaski describing to non-human Worf how humans were and how they improved since). If they were 20th century people, there's no doubt everyone would be cross at Worf, which ultimately accomplishes very little. Pulaski edified Worf with some deftness, he learned, they all moved onward. Worf also said "I don't understand their humor either" in "The Naked Now". As with any number of comments from Lwaxana Troi in her episodes, it's a sort of "speciesist" attitude and until we meet other species from outer space that, unlike Diana and Steven and Barbara and Brian, aren't hot but want us humans on the grill but are actually real... But a TV show made by humans for humans using allegory and metaphor, Worf was the 20th century caricature for that scene.