Why do football players have so many injuries compared to rugby players?
The other answerer’s have made good points. While the contact isn’t as frequent in soccer, it does happen, and the situations they find themselves in can make them more vulnerable than rugby players. When you are going all out for the ball with your leg is extended and you make contact with a defender who is also going all out for the ball there is a pretty good chance of someone suffering a serious joint injury or a broken bone. And so long as the defender does get a piece of the ball, its pretty likely to be a legal play. And one might note that if one rugby player tried to take out another in a similar fashion, there is a pretty good chance he would get a red card followed by a six week suspension.