There are two reasons to get into politics; a sense of service and ambition. These are not mutually exclusive and most who enter the field have far more of the latter than the former. Ambition is, perhaps the #1 predictor of “success” and success in politics almost always looks like rising to higher and higher levels of authority via gamesmanship.
The sad reality of this is that the more power people wield, the less capable they are of wielding it responsibly.
That, and local politics are remarkably easy to game; any goddamn moron can run and if they can get 100 or so of their meathead buddies to show up and vote, it’s a foregone conclusion.