Person A believes they work.
Person A says "we shouldn't use this on Persons B, C, D".
Pretty major implications about the integrity and suitability of Persons B, C, and D, and about how Person A suspects they have stuff to hide.
(In some ways this is a good reason to keep them around. Even if some people know they're crap, the existence and popular mythology causes people to reveal more than they otherwise would through actions like this.)