I wanted to do karate as a unit when I was teaching Phys Ed. The department chair, who's a good friend and great colleague said its a great idea, but the administration would never go for it. With his blessing, I asked the principal. He thought it would lead to bullying during the class, much like dodgeball, and it would be forcing kids to do a high risk activity against their own will. I explained that just like dodgeball (and everything else), it's the teacher's job to set the tone and make sure it's not tolerated. I'm a professional educator who knows what to look for, how to minimize the chances, and how to stop it immediately before it gets out of hand. He genuinely liked and respected my response, but said if I wanted to do karate and/or dodgeball, it would have to be after school. A voluntary activity such as those is fine; mandating them in class isn't.
I get where he was coming from. Forcing a kid who fits the bully's target profile to spar against say, the kid who just got a Div I basketball scholarship could cause some serious anxiety. I wouldn't allow contact during sparring, just moving and practicing blocking slow and controlled punches and kicks that won't land.
I'm pretty sure he was far more concerned with parents' and students' perceptions and dealing with them than what actually would've happened. And add to that the absurdity he'd have to deal with if a kid got hurt.
It seems like every time someone gets hurt, the activity gets banned. A kid tripped over another kid's floor hockey stick and fell into the bleachers, requiring stitches. No more floor hockey. A kid walked into the backswing of another student when we were doing golf. Golf was banned. The best part about that one was it was it was 10 minutes into the first golf lesson ever at that school, and the teacher had just finished telling the kids to stay behind a line 10 feet away for the 3rd time. $3k worth of golf clubs, bags, balls etc. thrown out by the end of the day. Tax dollars at work. All of this was at a high school level, so the kids knew better. I kept saying there will be a day when we're only allowed to let kids walk (not run) around the track because every other activity got banned due to injuries.