I think you're confusing villains and pests.
No one has suggested there should be no piracy, but ganking has nothing to do with piracy - which oddly enough is "the practice of attacking and robbing ships (at sea)". Gankers are not there to rob or otherwise make a living out of piracy, many don't even bother equipping cargo racks, they're just there to pester other players by harassing and attacking them for presumably psycho-sexual reasons.
If gankers genuinely engaged in piracy, I'd have some semblance of respect for them, but they don't, typically their load outs are designed to do nothing more than make another players ship go boom and this in turn forces other players to also load out in the same manner in an arms race that results in any other kind of game play being close to impossible in open. And when one group of players ends up monopolizing any particular game mode, then that unfortunately is a sign that the game is broken.