Were you unable to access the text of the article because of some paywall or barrier? Or are you reacting to the title alone?

The authors state very clearly that many of the victims lead a healthy life with enough movement and good food.

Why would be a 2x - 3x increase of cancers in young people unbelievable? The baseline was very low, so a two- or three-fold increase still amounts to a relatively small amount of extra cancer cases that you don't have to notice in your personal acquaintance bubble. The vast majority of cancer still happens in the elderly.