There is Free Speech everywhere
As Jeff said, not when you're a guest on someone else's forum. I'm not trying to take you to task individually for the tone of your comments, but I can't sit by quietly while a group "+1's" a course of action that would not only be legally questionable but is probably not tactically sound either. I've seen personally how complicated things get in court when you'd think a situation is clear cut. So far, you've done nothing to contribute to the discussion other than throw in some emotional arguments that don't stand up to rational scrutiny and then take offense when offered suggestions as to how best to prepare yourself.
Now, back OT:
The biggest mistake the fathers in both situations posed by the OP made was getting into and remaining in the "danger zone", i.e., close enough for the thugs to get to them with contact weapons. Getting beat badly enough to get put in the hospital is a pretty solid indication of failure of their strategies to some degree. Good hand to hand skills and training in how to deal with more than one attacker at a time might have been useful, but another tool comes to mind: OC.
OC would have been useful for several reasons.
1. It keeps you out of arm's reach.
2. It makes a nice area weapon.
3. It's usually taken as a de-escalation of force, a defensive tool.
4. Nobody goes to the hospital.
5. If you accidentally spray your child, well the effects wear off and no physical damage is done.
6. If these are hardened criminals, you've at least degraded their ability to attack you.
OC or any less lethal weapon should always be backed up by a firearm, but in these cases if OC had been employed and the BG's continued the attack, you'd be on much firmer legal ground if you had to use deadly force. "Ladies and gentlemen of the jury, my client used every means at his disposal to stop the attack and had no choice but to shoot."
I'm not saying that OC would have worked like a magic wand, but it's another tool in the box that might have been very useful in this case.
