I've lived in five communities with HOAs, including my current one, and I'm a past president of an HOA. Most HOA leaders (meaning board of director members or committee chairs) I've encountered are not lawyers. Some are, but I would say the biggest groups I've encountered are retired people and empty-nesters who have the time for this sort of thing.
The overwhelming objective of every HOA I've been in has been keeping property values high. So exterior home maintenance, landscaping maintenance, any exterior changes (especially colors),which plantings you can make, placement of stuff like basketball courts and trampolines, I think you get the idea. And the HOAs have teeth in their enforcement, because in every state I've lived in the HOAs can fine you and put a lien on your property if you don't pay their sometimes high fines for non-compliance.
In the areas I've lived in behavior problems are the purview of the police, not the HOA. So herbu is probably incorrect in his assumptions. Even in HOAs with security patrols, like the one I live in now, they are typically powerless; their only course of action is to call the police. Often communities like my current one and the last one I lived in have private streets and gates, and that means road maintenance and parking enforcement. Yeah, parking enforcement, because the police typically do not have jurisdiction over private streets. So if some jackass blocks your driveway you have to get the HOA to have the car towed.
The most restrictive HOA community I've lived in had rules that any visible window coverings had to be white on the exterior-facing side, and you weren't allowed to park any cars in your driveway or the street unless your garage, and every house had at least a two-car garage, was fully occupied by cars. Parking in the street overnight wasn't allowed at all. We had a full-size Bronco at the time which wouldn't fit in the garage due to inadequate garage door height clearance, so we parked it in the driveway. That was an extended disagreement, but I prevailed because the HOA refused to pay for a better garage door. HOAs are a PITA, but they do increase property values.