I've always had trouble with the "no pads is a natural limiter to the amount/intensity of the hits" argument.
That said - those hard plastic helmets are weapons. They can hurt a player a lot more than a skull. Not sure what to do with that conclusion.
I love watching NFL football but its obviously a form of killing people slowly for our entertainment. I don't see how it can sustain unless we all look the other way on the brain injuries.
The rugby players that I know tell me that their pain limits how hard they tackle an opponent. They would not like to see padding introduced because a player would trust their armour overmuch and increase the risk of injury.
In addition to the force of the impact, a significant difference is the form that you employ in making a tackle. In football a common technique is to put your head in the center of the opponent's body in order to help stop their force. In rugby, not wearing a helmet means you are _likely_ to receive a concussion if you do this (mostly from knees). As such, in rugby a proper tackle technique involves you putting your head to the side of your opponent, and using your shoulder as the primary point of contact with the opponent.
The upshot of this is that your head is involved in significantly less direct contact (though there's still some).
That makes sense to me, but then there's that "one guy" (not one guy) that is willing to push it too far and shifts the center of the sport towards the more violent end (e.g., Mike Tyson).
The OP mentions this, for example there are stern rules in the NFL against grabbing a player's facemask and cross blocks, but they still happen frequently. Furthermore, the games rules reward pushing the envelope (15 yards vs chance of serious injury to e.g., the quarterback is unequal).
You can make an effective argument that if you play football in the NFL you will sustain many serious injuries to your brain and body (as the OP does). I'd expand that to include college and high school football as well.
They would if they weren't wearing head to toe padded protection. It would actually hurt, and pain would limit the needless aggression. Works fine in Rugby (union and league) and Aussie rules, with players every bit as hard and aggressive.
Just look at the size of rugby players vs. NFL players. It is completely ridiculous to assert that taking the pads off players is the solution.
If you put some full backs from the NFL in a rugby game, players would literally die (and I mean literally, literally). They are massive. Seeing these guys in person blows your mind (figuratively).
[added] I don't know how good of a source it really is, but there are some infographics in this form that show a difference.
That said - those hard plastic helmets are weapons. They can hurt a player a lot more than a skull. Not sure what to do with that conclusion.
I love watching NFL football but its obviously a form of killing people slowly for our entertainment. I don't see how it can sustain unless we all look the other way on the brain injuries.