Yeah I know what you meant, just that it gave me a good laugh when you put it that way.
Anyways, hard tackling by itself does not cause injuries... I've seldom hurt an opponent while playing hard tackling. I use it to get more tackles in and break for a counter. I do believe that injuries are random variables put in the programming so it's more like a lotto draw or russian roulette. If the flag is called too frequently that's when injuries happen too many times.
In other words - Angry player + random annoying event = Injury
