Considering that the old quote is Cicero criticizing pre-dictator Julius Caesar for the way he wore his toga (and not, you know, all the things that Sulla might've put him on the Proscription Lists for), I'd argue its more that old people consistently criticize the wrong thing about young people, focusing on the superficial, rather than the substantive.

EDIT because I forgot to add:

This missing the mark is rarely because there's something intrinsic about old people and other people's haircuts. Its more that we are generally raised to respect (as authorities) our elders, and sort of subconsciously expect that people younger than us will in turn grant us the same respect. So the criticism basically comes down "they're not giving me what's due to me".

Meanwhile, if the criticism leveled against Caesar came down to "he's waaaaay too ambitious, and has already shown a propensity for ignoring social mores to get what he wants", then Cicero's criticism might feel more prescient, and less like an old man shouting at a cloud.

All of that said, its actually really hard in the moment to identify what will be dangerous to society before it comes up. So maybe Cicero had a feeling in his gut, but all he could come up with is "he's kind of sloppy with his toga"