Don't know if total ignorance is a blessing or not in this case, but....
Perhaps it has to do with how the animal is raised (grain vs grass?), or how the meat is prepared. Maybe there's something else in their diet or culture or even genetics which helps to offset it. Maybe they are dying of something else. Maybe the numbers of under-reported. Maybe cancer rates are more impacted by other factors, like smoking and drinking, and this is, relatively speaking, a drop in the bucket.
If you follow the Reddit comment linked and referenced from this thread that gives the high-level immunological summary of what's supposed to be happening here, it's hard to see how grass vs. corn fed beef could be making that much of a difference.
Grass-fed steak has about twice as many omega-3s as a typical grain-fed steak. And since grass-fed cattle are typically leaner, almost all cuts of grass-fed beef have less total fat than beef from corn-raised cattle.
Of course, Beef Magazine will refute those numbers with industry-sponsored "studies", but I tend to take them with a grain of salt (just like my steak).
Perhaps it has to do with how the animal is raised (grain vs grass?), or how the meat is prepared. Maybe there's something else in their diet or culture or even genetics which helps to offset it. Maybe they are dying of something else. Maybe the numbers of under-reported. Maybe cancer rates are more impacted by other factors, like smoking and drinking, and this is, relatively speaking, a drop in the bucket.