I coached the boys team at Bronxville for 4 years. I'm not going to weight in directly on MC or that situation, but I am going to weigh in on the Bronxville girls coach, Jim Mitchell.
Mitch is a legend, and someone I feel lucky to have watched coach. It sometimes amazes me he doesn't get more recognition for all he accomplished, I think you could argue he is the most successful middle distance coach in American HS history. I don't know the exact stats anymore, but the Bronxville girls under Mitchell averaged a season best 4x800 time of about 9:16 during his 35 year tenure. This is a public school with fewer than 100 kids per class. Yes MC was a standout, but he had no shortage of star runners, many of whom went on to run successfully in college and beyond. His relay teams were in contention for NY state titles every year, and often national titles as well.
The thing that amazed me about Mitchell was how simple and understated his coaching was. Practice for the girls rarely lasted an hour. They warmed up and got ready to go on their own, checked in with him, did the workout as he watched, offering the same simple advice and encouragement as they ran by ("good, stay relaxed, run smooth"), chatted with him for a few minutes, and then jogged off. There were no big speeches, no crazy long runs, no interventions into their personal lives that you hear about with so many other dominant programs. Just an expectation to show up on time, do the work, and be a competitor. Most of his kids ran about 30 miles per week and had very full lives off the track.
Mitch was someone his athletes looked up to, craved affection from, and wanted to succeed for. For the most part, from my observations, he succeeded by offering praise and positivity when he saw what he wanted (hard work and competitive drive), and simply not responding to behavior he didn't like. After one of his athletes pulled the classic high school collapse just before the finish and dramatically crawl across the line moves, I remember her looking up at Mitch and him shrugging and saying "I don't know, I can't help you" before turning and enthusiastically congratulating another runner on the team. She never did it again.
His approach worked. It let kids figure themselves out and decide for themselves to become tougher, faster, and more disciplined. There were no arbitrary rules that made kids feel like they were being micromanaged. Just clear signals that they were on the path to success or not. In particular, his approach worked for a town like Bronxville, where the pressure to succeed and stand out is immense, and many families expect a school system to drive their kid to succeed while also being immensely accommodating of their individuality. No easy feat in education.
I can see how when "bullying" starts, Mitchell's approach could be characterized as "doing nothing". But bullying, like all human behavior, is complicated. Making people change their behavior is never as simple as telling them what they can and can't do. In my experience, Mitchell always saw the bigger picture, and always worked, in his subtle way, to move his kids toward better choices and growth. I'm sad to see anyone taking shots at him, especially to sell a book, and sure hope most people in the running community aren't buying it.