[nonbel]

There was no confusion of correlation and causation in my post. It is a clearly stated correlation.

Broad spectrum sunblock may be less than perfect, but until recently all sunblock was transparent to UVA. It blocked UVB which prevented the natural sunburn/tan/thickening response without preventing the DNA damage.

Given the huge growth in skin cancers since people started wearing sunblock it seems likely that it was actively harmful for this reason.