what are you basing this on? a large number of my friends are from a local rugby club, i would say they suffer as many injuries as those that play football. They certainly suffer more serious injuries. I would also say the long term affects of playing rugby seem worse. Ask anyone that has played for 20 years or so (you'll be able to tell who they are by the disfigured nose and ears), most of them can barely walk and suffer long term knee and ankle injuries.
Certainly the theme amongst most i know.
Rugby I played for a fair few years and the worst I picked up were a handful of scars and the odd shoeing in a ruck.
In football, I have had my knee ligaments ripped, my ankle almost broken, cracked my head open three times and almost snapped my wrist.
Add to that I've broken two people's ankles in a tackle/collision and someone's arm. (Bizarrely) As well as that, most of my friends have suffered similar things, the odd injury in rugby but far more in football.