it's not exactly their fault.... at least for the farmers that were under an oppressive regime for 50 years and relied on ideas that were literally a thousand years old.
If anything you gotta give credit to people like Yao Ming for absolutely inverting the population on ideas like this.
Hi, uh, try to understand that China is a huge country with a wide range of degree of education and vastly different cultures and values. What you said is basically like "Hur dur fucking Americans fuck their siblings so stupid" when it's a stereotype on rednecks
This is only partly true. and more false than true: http://www.elasmo-research.org/education/topics/p_bite_on_cancer.htm TLDR: They are not immune but remarkably resistant. "Research by Dr. Robert Langer of M.I.T. and other workers has revealed a promising anti-tumor agent obtainable in quantity from shark cartilage. Shark cartilage, it turns out, contains a compound antagonistic to the effects of angiogenin, called (cleverly enough) 'angiogenin inhibitor' - which does just what it sounds like: inhibits the formation of new blood vessels so that the proto-tumor starves or 'chokes' in its own waste products." Also eating sharks for health is not an "incorrect medical belief" but plain superstition, not based on the assumption they don't get cancer. The major idea here is - of course - that sharkfins are somehow an aphrodisiac.
Logic would say that if sharks don't get cancer, you should eat what sharks eat to also not get cancer, not eat the Sharks themselves. So the sharks are screwed for the reasons listed PLUS bad logic.
If anything you gotta give credit to people like Yao Ming for absolutely inverting the population on ideas like this.