> People with two broken PCSK9 genes have close to zero LDL and have noticeably completely plaque free arteries as adults. I do think this does pretty fatal damage to the theory that you must have some other health issue for LDL to be bad.

i'm not sure i follow this extrapolation from low-ldl individuals to any direct statement about causes and effects at higher ldl levels.

if there was, for instance, some thought-harmless virus endemic to a large portion of the population which somehow caused plaque buildup but only at sufficiently high ldl levels, people with naturally low levels their entire lives would still have plaque free arteries and we would still, as we do, see a broader range of plaque buildup among people with high levels. how do you propose to distinguish this hypothetical (and admittedly most likely biologically incoherent) explanation from yours by only looking at people with naturally low levels?

your assertion that such individuals are an excellent approximation to an experiment on the arterial health effects of lifetime low ldl seems reasonable enough, but you then appear to draw unfounded conclusions about the nature of potential inverse effects at higher ldl levels.