Playing the meta-game, there seems to be two discussions happening, one over the other. One is a black/white morality equation, and the other is a shades of grey legality one. Using one to argue the other really just adds pigeon turds to the chessboard.
As to the grey side of the argument, on one side "all art is theft", and on the other unlimited patent and copyright leads only to Disney. I don't want a Disney of knives, so that's why we have limits. The axis lock patent expiring is in general a good thing, it allows more innovation, and still provided for the profiting of the designer for a time. Ganzo used that patent without permission, and no plausible excuse. Other companies may have been inspired by it, and made changes to sneak around it, but that is how that system is supposed to work. Now the closest to the discussion at hand would be Hogue and the handle. Sure, it does look to be inspired by the Pardue design, but they changed it. So we can ask, did they change it enough? That is a "how long is a piece of string" question. Handles are the shape they are because they work. Culturally, knife people could start using wording like "it has a Pardue style grip" and maybe that's something that will happen. In that way it becomes a pattern along with words like stockman, folding hunter etc. In shooting you have "5.56 p-mag adapter". Its just a way of referencing the unimportant parts, to focus on it in a different way. Because if we do not allow any re-use of ideas, then the multi-blade slipjoint dies sometime back in Sheffield a very long time ago. The legal is an outgrowth of the culture, and right now the culture is okay with using ideas that have been around a certain length of time, but is not okay with using someone else's ideas right after they develop it, or in such a way as to ride on the other parties reputation. So to answer the question of why do some companies get a pass and others do not? "We" decide. Sometimes that sentiment takes time to swing, Hogue took some heat for a little bit, but it seems like its settled out. And Ganzo still sucks.
Anyone interested in the big river site and just how hard it is to pull fakes out circulation, thewirecutter.com has a series of articles looking into it, and some of the complexities. Suffice to say, if you think its simple, go ahead and read them, because the problem is far bigger than you think.
To me this stance seems contradictory to the values many espouse against copying . So copying is very bad, but so is getting out of that business (not copying) ? 
