All sports can be dangerous, we know of a friends son who walks with crutches, because he was tackled badly at football, or MIL's friend who is in a wheelchair after falling of her horse. Our school lost a pupil on a skiing holiday when a loose ski hit the girls head. This a rough Yorkshire comprehensive, no more skiing holidays. Sadly people drown swimming.
The culture of rugby, I think I better put on flame proof clothing, my boys have played RL and eldest now RU, all very working class clubs, the RU club started as old boys from the town's secondary modern school.
We have no issues with bad behaviour, in fact all players and parents have to sign conduct forms at start of each season. Both boys played with girls up to 11. They have been and are regularly refereed by girls/women and are even more respectful to them, than the male referees. Most games are watched by mums, girlfriends and wife's.
Ds1 has been on numerous tours and stays with his rugby, alone from age of 10, we have never felt he was in any danger, at 12 they went on a midnight raid to wake up 14 year old girl guides, got scare of their life's when girls attack with water bombs. The guides complained, well leaders, all ten players, including Ds wrote letters apologizing. The following year girl guides came back on same weekend and both groups spent 4 days messing around together, Ds still in touch with a couple of them on facebook.
I fear the culture needmore speaks of is the rahrah end of rugby, especially privately educated boys/men with lots of money and a life time of privilege and been told you're are better than the rest. Cricket tour of Australia has had similar issues, Oxford/ Bristol universities and their private school clubs seem to hit the headlines ever year.
Ds1 looking to go to university this September, so his 3 chooses 1st- about 8% private has 3 rugby teams, shown around by people he knows from local clubs and girls team captain. 2nd choice- 5% private has both RL and RU, not RL heartland, shown around by girls team captain, who told students/parents that they are diverse team, no drinking culture and you will likely to be removed from your course if you act stupid. 3rd choice- new and less than 2% private, no rugby, either join local teams or start one yourself.
So think culture often comes from the players and their backgrounds, not the sport, especially where you have lots of money and privilege thrown together, which I suspect is the case for most on this thread and the universities your friend and your student DC's go to needmore
I know not all private school children are like this but sadly you do often meet them on rugby pitches, with their private school walk, ie my b*lls are bigger than ours.