My entire spare time was devoted to full contact kickboxing on a competative level. So does that make me an expert?
Good question. Competitive = sport.
However, I do agree with your points, many of them, so I'll just mention that many budoka, modern practitioners of any fighting art, do separate sport from self defense, even those in sport should know the difference, and be proud of what they do too.
Both are better than sitting playing video games!
This may not be the best advice, it could get someone killed, in fact its not advice, and your situation may be very different. BUT,
I have been involved in a situation where the group physically assaulted me (beyond threats) twice. The first, a ring of 10 guys of opposite race beat the crap out of me in 8th grade. One reason I was pushed into martial arts training although over the years it really evolved out of that.
The second time I was about 20. The group was much larger, probably 20-30 guys and a few girls, also opposite race, ranging in age from 15 to 19. This is how I handled it, and I was blessed to say the least.
I remarked about how they were p**sies for all having to take me on at the same time, that if they were so bad they should do it one at a time. They went for it. I pointed at someone I thought looked kind of strong, he threw his friend out. In my own mind I considered that I may be about to get beat down but I acted like it was a casual walk in the park wipe this guys face on the floor. It was very short - he threw a lame punch or two and I hit him twice. The bigger guy came out (now HE was on the spot with friends). I hit him in the stomach really hard and knocked the air outta him. At this point it was basically over, they were all laughing at each other and the aggression was somewhat diffused. They could have laid into me at any moment but for whatever reason, the psychology of not being a victim, in this particular instance, worked. Two more guys came out and they weren't even doing anything, again, a few hits, low hi, hi low, side kick. Done. About 30 minutes later a bunch of them came back around and said I was invited to join their gang, to be the first White Guy. I don't even remember what I said, I think ok, I was still coming down from the adrenaline rush.
This had all started cause I choked some guy out wrestling and he went and got all his friends down the neighborhood. Because I worked in a program for some of them I know many had records and the energy of the senario could have gone south fast. It didn't.
Good luck. Psychology counts for a lot. Weight training, wrestling, sports, martial arts, all those can help with that end. The way someone stands and walks (not arrogant mind you) can often do more than any technique, spray, or weapon.
ST