In every single human activity that involves a scoring system, you'll find people cheating and faking their score. I guess it tells you a little something about humanity, though there's worst things we do.
Acknowledging it as the hidden rule of any ranking on the internet, where it's too complicated to see with certainty who cheats and who doesn't, can help getting some perspective on the matter. Disregard the dubious scores, or just disregard the entire leaderboard and forget about it, it will ease your mind.