Old guy here. I think it can be agreed that it's a positive development that coaches no longer have license to punch an athlete. I don't think that was ever common, but it's good that it's almost unheard of today.
However, the fact that Benoit had the ability to shrug such an event off was undoubtedly a part of her mental makeup that helped her as an athlete, and something that many (most? all?) young athletes struggle with today. Staying focused despite discomfort, dealing with unfairness, being held very accountable to a high standard--you can make a case that a Bob Knight style coach was once able to develop these traits to a degree that is not possible now. Punching is certainly not a desirable way to build these traits, but I wonder if these traits are being developed much at all in today's "supportive" sports environments.
Creating a hyper-intense and uncompromising environment where athletes have no choice but to rise above their perceived limitations is how coaches used to see their job. Hell, that process what most sports movies are all about--Hoosiers, Remember the Titans, Miracle, etc etc. It's how we used to see the way a coach and team functioned. "Vince Lombardi treats us all the same--like dogs," etc.
It's undoubtedly true that some old-school coaches also used "being demanding" as an excuse to venture into general assholery (Bobby Knight did this I believe). But it's also true that today's coaches can't demand the same kind of accountability and intensity that was typical 30 years ago. And it's possible that this represents a real loss. Today the role of the coach is to "help" kids, "mentor" kids, "support" kids. That's certainly what most young people expect. And I'd say, yes, absolutely these things are important, but it used to be that these roles were secondary to the idea that coaches were supposed to challenge kids and hold them accountable to a high standard. Your friends and teammates were there for support. Your coach was supposed to make you great.