Well, it's pretty clear in those posts from the other place. Frankly I'd be careful about cross posting that from there.
There are at least two issues mentioned there.
A. Some people were buying these pimped 6's under false pretenses, thinking they were real and then trying to get them serviced.
B. it's his Intellectual Property and people are copying/stealing it - it says "he hopes this continues to happen (the Po'Boy conversions), without creating copies of his flagship knife."
A Po'Boy is modifying the handle, bolster, etc. to make a new version of an existing knife. Grinding a Bulldog into a 6 grind and then giving it all new boat tail scales and liners, etc. is clearly making a Po'Boy 6 which Mr. Emerson did ask people to stop doing.