There is a large segment of people that will say things like " running causes arthritis in your knees". This is what I was directing my comment at. Running, on its own, does not cause your knees to become weak or necessarily damaged. There is a chance of an injury occurring, but that does not mean that people should not exercise in general.
there is nothing different from "exercise over time leads to injury" and "being alive for a long time leads to injury" . Sitting at a bus stop has risks, sitting in your house has risks, walking anywhere can have one bad step that can do absurd amounts of permanent damage. None of this means that exercise will cause injury.
I have a permanent injury to a shoulder, so I somewhat understand your perspective .It happened from several odd falls, and then one day it came out while lifting a bucket and tore things up when it slid back in. I will never be able to do a pullup unless I can nearly one arm it with the other side.
My statement is not ignorant, it was targeted at people who are misinformed and loud, and the opposite of ignorant. Like I said, because of science. If it is arrogant, it is only because of the number of times I have to hear the nonsense about the cause (not risk) of injury being exercise.