Supongo que lo dice por esta cita, atribuida a Sócrates (aunque en realidad fue acuñada por Kenneth John Freeman en 1907):
The children now love luxury; they have bad manners, contempt for authority; they show disrespect for elders and love chatter in place of exercise. Children are now tyrants, not the servants of their households. They no longer rise when elders enter the room. They contradict their parents, chatter before company, gobble up dainties at the table, cross their legs, and tyrannize their teachers.
Hay un artículo en la revista Science Advances que da una explicación a este fenómeno:
Kids these days: Why the youth of today seem lacking