It's worth noting that there are two sorts of posts that people will try to game the voting process - submissions by people who want the status of higher karma among their peers and submissions by startup founders who want "traction"[1]. That is to say, people believe there is actual, real tangible value in getting upvotes. To that end, while it'd be nice for HN to be more organic, unless there's a penalty for gaming the system it's not going stop just because people ask nicely.

[1] The traction you get on a site like HN is useful for feedback but it probably won't covert to sales unless you building something for other startups. It's not real take-it-to-the-investors traction.