albino boo said:
All I'm seeing is the seat belts make people take more risk argument. The energy of impact remains the same, in one case a person has padding and in the other its does not. You need to stop and think logically for a second, which is more dangerous being hit by 220 lb weight while wearing padding or being hit by the same weight while not wearing padding.
Your logical summation is based on a false premise, that the way impacts occur and the force and speed of said impacts are the same in football and rugby. I played both games in my youth and can tell you that the way you approach and tackle and the way you block and finish in each sport is different. But I do not expect you to take my word or my anecdotal evidence into account, so here's a research paper done for the NFL Player's Association that covers six years of injury metrics.
http://www.esquire.com/cm/esquire/data/Dangers-of-the-Game-Draft-Esquire.pdf
From the paper: Teams averaged 3.2 injuries per week (games are played once a week). 59% of players suffer some injury each year. Nearly 40% of injuries are severe enough that the player misses at least one game. 10% are severe enough that the player is placed on IR (Injured Reserve, this essentially means the player misses the entire rest of the season). A direct comparison of this information to that in the article about rugby that was linked would not be sensible, but a 20% chance per game of there being an injury is nothing compared to the 6.4 injuries expected per game (3.2 per team) in Gridiron.
Edit - A significant addition of information here regarding England Rugby Premiership injury data, which should be much more comparable to that in the NFLPA study.
http://irbplayerwelfare.com/?documentid=75
The ERP study's metrics are significantly different, so it's hard to make direct comparisons but the one that jumps out is that there were 1.9 injuries per match for the EPR compared to 3.2 for the NFL. So about a 40% increase in injuries per match/game in the NFL over the ERP.