Have you ever seen a "canker" on a tree? An insect burrows into it, and it grows a canker over it. An insect burrows into that and it grows another canker on top.
An old friend explained to me that this is how one silly thing grows into one massive fraud - like bizarre religious cult. One lie or stupid thing is pointed out. Youd think people would go oh, well, I'll grow up and accept the reality. But no - they grow a "canker" over it - some ideological mechanism that covers the lie. Now the lie is that bit bigger.
Canker has the same root as "cancer".
I dunno - there's a massive list of cankers - have I spelled that correctly, ha ha - in martial arts.
The bestest are those which make a concept unfalsifiable - i.e. no matter what happens, it seems to prove the lie. So, if my qi power knocks you out without touching you, that proves my qi power. If it doesn't, then you're not sensitive to qi - which also proves the "reality" of qi power.
Most of these logical fallacies and lies are so old the Ancient Greeks knew about them - like Aesop's fable of the marvellous athlete.
Actually, it's no big deal to be afraid of sparring - and a simple training plan would get most competent people past that barrier. It's when hoaxers make it seem like there's a lazy option - then cankers are needed. And yes, it is ****ney rhyming slang.