Even in busy NYC airspace if an avoid for weather is needed, in the opinion of the aircraft commander, then a deviation is required. ATC here were maxed out and were annoyed that his plan did not match the view of the person legally responsible for the safe conduct of the flight and the lives of those onboard.
Pilots do know that weather avoids make ATC work harder so don’t tend to ask for them “just because”. I have sat at the end of the runway looking at a massive cell 2miles off the end of the runway and declined to depart. A local lo co did depart with an immediate sharp turn, he avoided the weather. I was not prepared to risk the lives of my passengers in a wide body, he was in his 737. We were both correct and ATC can go hang if they disagree - it’s not their lives on the line.
ATC here were out of order and need to rethink - but we can all get like that when we are up to arse in alligators. Maybe a little review and rethinking is required - nobody needs the atttude. The end result was safe, ATC got stressed as they ran out out capacity, it’s not the end of the world, we are all human.