Your coach is an idiot with a superiority complex who assumes he can act like a brat because he's older (ironically). This is sort of like my 2 years older brother. Back when we were little kids, he'd assume he had the right to act like a brat because he was older than me. He had this crazy idea that there is no such thing as an older brother being arrogant towards his younger brother while the inverse was a possibility (a younger brother being arrogant towards his older brother).
This is just a silly anecdote, but my point is that it's directly analogous to what we're discussing right now. Older generations assuming they're smarter than the younger ones. Not only has it empirically been proven wrong, it's brashly arrogant, self-indulgent, heavily delusional and if you ask me, it displays behaviour that only little brats indulge in.