That 2000 study compared two groups, one that didn't wear sunscreen and spent little time in the sun and one that wore sunscreen and spent a lot of time in the sun. In order to test the difference you would need to control for TIME IN SUN.
The study itself concludes that it is time spent in sun that is the crucial factor in melanoma occurrence. That would seem to run counter to your post.
What the vast majority of studies have found is that the sun is likely to give you cancer the longer you are exposed to it. Sunscreen reduces this risk somewhat, however it won't save you if you wear it and spend every sunny day out in the sun.
