These ‘X % of cancers are due to lifestyle’ statements are an extrapolation from observational data we know is confounded and are an overestimate for sure. What they mean by ‘lifestyle’ isn’t even consistently defined, and thus has no predictive let alone explanatory power. Just look at the data from animals, they get cancer all the time and they aren’t eating cheerios and binge drinking. Cancer does effect smaller animals just as much [1].

[1] https://www.nature.com/articles/s41586-021-04224-5