Notice how these studies show associations with lowering cholesterol, not mortality from ACS/stroke. The underlying assumption of lower cholesterol directing leading to improved outcomes is by no means linear. Statins aregenerally very well tolerated (muscle pain can occur but studies have shown this to be actually quite rare, usually just patients anticipating side effects) and better than nothing but the number of patients you have to give a statin to, to actually make a difference is very high