While I have no statistics either way, I have heard, and I believe this statement to be true, that people are far more likely to complain than praise (on a forum or otherwise). When someone is happy, they will go along doing what they enjoy, but when something upset them, they will complain. So seeing more complaints than praise doesn't have to mean that more people are unhappy, just that they are more vocal. I'm not saying that most people are happy, just pointing out that seeing more negativity on forums isn't proof that the majority share the view.
I think this is probably because those players aren't interested in any interruption or challenge. For example if I'm sitting down building a puzzle, I wouldn't appreciate if someone ran into the room trying to steal pieces from me. Silly example maybe, but I think you'll understand my point. And I think it's fair that not everyone want a challenge (or another kind of challenge).
Unfortunately some challenges (PvP piracy) depend on finding someone to pirate, and I think that one of the issues is that it's so hard to find anyone outside specific systems in the first place. For a pirate, you don't just have to find anyone (gankers probably happy with anyone), but you have to find someone which, right now, got a valuable cargo. Because there's no (in my opinion) engaging gameplay loop to hunt for them, you wouldn't be happy after spending an evening looking for someone to pirate and find none at all. All you do is wait at a certain system or jump around and hope you find someone, with little thought around it.
I would argue that being a PvP pirate have bad game design.