European travel, elections, mass media, and other “gloriously normal” things might sustain the rest of society because society has effectively given up on meaning and has therefore settled for such things in substitution, but they are shallow and hence aren't fit for a sensitive soul like Franny's. Salinger snarled at such things because he saw that they're banal.
Camus would have agreed, but he took the analysis one step further and said it could be proper to engage in such things with full force as long as the person approaches the banality with the Sisyphian attitude. Camus, for instance, said Don Juan's lusty pursuit of women was a proper thing to do given man's absurd existence. Don Juan's activities were, no doubt, banal and vulgar, but he understood the whole time that there was no ultimate meaning in the sex. The same goes for the artist who goes about his work, knowing it is predestined to extinction and oblivion, like Sisyphus' rock is predestined to roll back down the hill. Don Juan and the artist plod on anyway because that's their way of revolting against man's absurd state: By insisting on wringing something out of life, even though it will ultimately prove pointless, these “heroes of the absurd” smiled at fate instead of snarling at it, but never denied it and never fooled themselves into thinking the pursuits are important.
That's the difference between the heroes of the absurd and the contemporary man on the street that Salinger loathed. Most men don't have the Sisyphian resignation in their pursuit of the banality that Holden Caulfield detested and Zooey screamed against. People are pursuing banality with a banal mental state. They have intuitively given up the hope of finding meaning–they no longer expect the silent oak tree to respond to their higher aspirations or ideals–so they've opted for banalities instead. But it's all unintentional. They're not “conscious”–not resigned nor hopeful nor despairing. Just plodding. Sisyphus, the artist, Don Juan–they're nihilists, but conscious and resigned nihilists, whereas most of the rest of society consists of intuitive nihilists.