Your post is full of assumptions. How are you ascertaining whether or not a curb cut is legal or not? Is it possible that you are perhaps blocking someone’s parking spot that they paid nice money to legalize? If they’re sitting by the window and waiting to make sure their driveway is clear it’s probably an active driveway. They are probably sick and tired of getting parking tickets due to not being able to park in their own driveway.
Another point; in order to pull into a driveway a driver needs enough space to turn. Would you rather take the chance of them nicking your car on the way in? I think it’s nice for them to tell you where you can safely park. I suggest that when your neighbor greets you with a smile you should return the gesture. You may very well be judging him for no reason at all.