I'm not siding with any side, but if you, yes you, were doing your job, whatever your job was and somebody you did not know and had never seen before was standing across the street videoing your every action, wouldn't you want to know what he was doing. Add to it that it is after dark and not when you see the average person video taping.
Okay, now that you want to know, put a badge on, the purpose of which is to represent every person's safety and well being in the community that you serve. Are you as a police officer, responsible for public safety, going to ignore the odd behavior of the guy with the video camera that you do not know. They were doing their job. The police had every right to inquire. Maybe they need a little PR training, but the circumstances warranted the inquiry. Go to any small town and do the same thing at night under similar circumstances and see if you don't get a similar or more aggressive response. The reason there was a handful of officers present is they did not know what they were dealing with and were not going to know until they investigated. Took them more time than was necessary because there was no cooperation on the part of the alleged "citizen" (we have no proof he was who he claimed to be).
Being within your rights does not make you right.