There are certainly sadists in most institutions, no doubt of that. Sounds awful. There's nothing quite like realising a colleague, boss or teacher literally wants to destroy you out of nowhere, and would be happy to see you and your ambitions wiped off the map.
The comments from my musician mate were more to say "that's not how musical talent works"—ie not through smashing your hands bloody trying to play faster and faster.
To paraphrase he reckoned the best musicians he had known got there without the blood loss, and the rest ultimately weren't going to be able to keep up regardless of effort. Also said Whiplash didn't really understand the musicality that "real" jazz people are obsessed with.
