The body needs SOME. Evolution doesn't care about when you die, just that you reproduce first. Even the highest cholesterol cases generally have kids old enough to have their own kids before they die. That is enough for evolution to not care.

As someone who lost the genetic lottery (has the high cholesterol gene) you bet I care. There is every reason to think that treating cholesterol will increase my lifespan - I'm hoping for quite a few more healthy years.