I lived most my teen years in rural Nova Scotia during the 1970s.
Almost always, fights (with weapons or not) were fought one on one.
If someone else jumped in, another person would immediately even up the odds.
Battles between groups seldom happened; but when they did, the time, place, and number of combatants were agreed on prior to the fight (sort of like in the film:"The Outsiders").
The very rare time that someone got swarmed, the victim always had lots of older brothers and "cousins" that would take retribution on the entire group of attackers sooner rather than later.
You have to remember that back then, most families out east had 5 to 7 kids.
No one ever "got away with it", yet the RCMP were never called.
Rural Nova Scotia was quite a unique place back then, as there was absolutely no hazing at any level of schooling.
Again, older brothers and relatives made hazing too dangerous a pastime for anyone to even attempt it.
We seldom saw any females fighting, and never saw them strike a male, or an adult of either sex.
I feel pretty positive that back then, if they had tried either of the latter two scenarios, they would have been knocked the "*" out.
I was always tall for my age and an A student, so dealing with bullies was a common occurrence for me.
My father taught me to attempt to talk my way out of a fight or simply just run away.
However, if neither of those options worked or were not available, his advice to me was to "hit first, hit hard, hit often, and don't stop until they back off, THEN RUN".
This certainly helped me in my early 20s; I worked as a bouncer for 3 years at three of the roughest bars in Calgary, and I never had to strike anyone as I was a very good talker.
Verbal persuasion almost always worked; on the rare occasion it was unsuccessful, it just became a wrestling match between a drunk customer and a sober bouncer.
In my opinion, the changes in Canadian criminal law since the 1970s have emboldened pre-teens and teens to do anything that they want, with very little fear of substantial consequences.
It's not movies, music, social media, or even parenting (though it's certainly tougher for single parent families) that's allowing this to happen, it's the laws that are currently on the books.