I don't think that article is about pointing fingers or victimisation. It is empowering people through education. Sure, lifestyle factors only account for 1/3 of cancers. By eliminating the lifestyle risks it can give you a sense of control, reduce cancer risk, and reduce anxiety related to fear of recurrence. I reckon this is a huge win!
You say that cancer can not be avoided. If this assertion was true then surely everybody would have cancer?
Smoking is just one example that increases cancer risk. There are various others such as obesity, poor diet, alcohol intake, and UV exposure. However, cancer is a multifactorial condition which means that the elimination of the modifiable risk factors will not prevent developing cancer, but it will reduce the risk. Other cancers can be attributed to genetic and environmental factors... and there are some types of cancer that currently have unknown causes.