"I see no hope for the future of our people if they are dependent on frivolous youth of today, for certainly all youth are reckless beyond words... When I was young, we were taught to be discreet and respectful of elders, but the present youth are exceedingly disrespectful and impatient of restraint"
Between the two hypotheses a) "society has been declining for thousands of years" and b) "older people tend towards grumpiness" I know which one sounds more likely :)
Although Hesiod's "I see no hope for the future of our people" may be vindicated by the fact that his culture no longer exists.
Perhaps cultures stagnate and corrupt over time, and complaints about youth is a symptom rather than a cause? Perhaps the collapse of a civilization every now and then is one of the mechanisms that keep human societies sustainable in the long run?
There are interesting questions here, but I don't think the older generation complaining about the younger generation is one of them. Not in and of itself, at least.
Among English speaking peoples, toughness has on average (i.e. not including people who hit restart by moving to frontier areas) probably declined monotonically since around 1000 AD.
How does JC get off? Well, what are going to do? Boycott him? Challenge him to a duel? A mixed martial arts match? Regard him as background noise, a minor nuisance like a loud, smelly bus stop, and move on.
But remember this in 10 or 20 or 40 years when you are tempted to say bad things about the young of that day.