I don't know if he really counts as an employee of the HOA in this case.
There are tons of books and studies on gated communities and their poaching of public resources though. And the legal view is going to be very murky as to whether or not the sidewalks in this community are public or private.
Generally a truly wealthy community will set itself up as a minimum type of municipality which is essentially defacto the HOA. However as time goes on and say the cost of fixing the road or the sewer system etc become cost prohibitive they allow more and more encroachment of the surrounding cities....which they have mostly not wanted because of tax issues; but eventually there is a point where its likely having the gating wouldn't be particularly legal any longer as they are essentially using full city services. Some of the gated communities also eventually ask for full regular police patrols which takes away from them being able to argue they are private as well.
I have no clue about this particular community.