perhaps this officer is on paid detail to that area or a specific business in that area. The car is as close to the curb as can be, and isn't blocking any traffic.

He also is not blocking a space that a civilian could use, it seem to me the operator of that vehicle took every precaution he could to minimize his footprint there so he would not interfere with the residents or businesses. this is a cop who took the time to be as polite as possible and this is how you thank him.