Sarcasm not withstanding, the times when a baby has to fly are virtually nil. It may be more convenient for the lifestyle of the parents, but it is almost never required. And, most Americans think "if it is was is most convenient for me, I do not care what suffering it may inflict upon others."

Yes, some adults can be disruptive as well, and I do not hold them in high regard either. But, that's not the discussion at hand. Subjecting others in a confined area to a baby screaming is rude and thus a sign of bad character.