It is bad to distribute them, because then more unsuspecting people like you buy them thinking they have a rare morph of something, and it turns out to be a hybrid. In addition to that, if you do what you propose and breed them back to more convicts, wrongly thinking you have a "pure" convict after the third generation, and you go and give them to people as convicts, before you know it everybody's convicts have a bit of red devil in them. And nobody has convicts anymore.
Bottom line, it is bad for the bloodlines and bad for the hobby to distribute hybrids under the guise of pure species. Even if you tell the people they are hybrids, who's to say they wont go and pawn them off as purebreds.