It addresses the point that people who spend more times indoors aren't making up the bulk of the cancer rates. Since they're at significantly decreased risk to those who spend more time outdoors. So the increase is more likely from the tanners, instagram models, tanning salon goers, etc. And not the tech engineer that hasn't left his closet in 13 years. I thought your argument was that excessive UV exposure does not cause cancer and if it wasn't I apologize.
But I will concede the point that prior to sunscreen we may have had a time limit on how long we could spend in the sun. With the products now we can be outside all day every single day of the week. And sunscreen is not 100% protective at all, nor is it often applied properly. So sure, that can be a factor to rates increasing. One of many possible theories.