You did the right thing by yelling at this guy. It's like one of our supreme court justices described pornographic material. He could not describe it but he "knew it when he seen it". Thats sounds like what you described. You know what you saw.
I have been around this sport for a long time and I've seen clowns being stupid and I always said I would never do it but I've also found myself on that line before and I thank God I didn't cross it with my son.
I witness DOUG747 in action this weekend with one of his wrestlers that was being, shall we say, less than acting in a sporting manner after a match and DOUG747 took care of business right then and there. He didn't abuse the kid but he let him know that stuff was not going to be tolerated. I also know it was not his own kid that he put in his place but I would bet my house that the kids father or mother didn't have a problem with it.

Here is the catch 22 fathers find themselves in, you tell your kid that you have to work hard and train like a mad man, eat the right food and get your rest, your kid does it and they still don't win the big match. One of two things happens; (1) they throw a fit right there on the mat or (2) they look at you and say now what smart guy, I did what you said and I didn't win.

How you as a parent react to this situation will often determine what your kid gets out of wrestling.

I know throwing your kid against the wall and choking him out is not the right thing to do.
DOUG747; if the guy who did this is reading this post, he is the ahole, not you.
This is a tough sport done by tough people and having said that I think the best thing to do would have been have your wife go get a cop and the husband follow the guy and make sure the kid was going to be OK. Let them sort it out and you would be sleeping better..
Just my 2 cents..