Some of these knives are clearly just fantasy wall hangers that are in no way intended to be practical. I actually have no problem with that - they are decorator stuff, and while they don't fit my personal tastes, neither do most of the stupid little nick-knacks people put on shelves around their houses.
There's a big difference between a ridiculous looking fantasy knife that's intended purely for decoration, and a tacticlol knife that's designed and marketed as if it's an actual practical self defense tool, being sold to people who will only ever have to defend themselves from a monster attacking them in World of Warcraft.