Photography in Bowie Town Center illegal?

Today I decided to get a filter for my 50mm lens from Ritz camera in Bowie Town Center. Since it was such a bright day, decided to try and freeze the water droplets of the water fountain on the circle there. A 'cop' (BTC security) pulled over and told me making pictures was illegal. Never engage in a discussion at this point, just let them go, but of course I decided to challenge this concept a little bit more.

I have made many pictures in BTC at times before. One time it was a little bird, to test out my new zoom lens. Ok, the pavement was on the background, but otherwise it was just the bird. Is that illegal too? Today I ran into a spider, who had made a rather intriguing web. I had never it this way before. So, that's a close-up, or is illegal now because the BTC light pole is on the back drop?

On the way out, had to wait at the traffic light and took a picture of their signature water tower. Is that illegal?

Downtown Silver Spring had a crisis like this some years ago. Security would approach people (me too once) to question/challenge their motives when using a camera. The public cried foul, and challenged the mall management by organizing a massive public photo shoot. The reason is that this area is leased from Silver Spring to this company, who then take care of the upkeep. But does that mean they own the street, and you can't make photos there? In an indoor mall the rules are perhaps a little more clear, that's a private area, not so public. Yet, plenty people use their cell phones, or little point and shoot. But when you walk around with a DSLR, suddenly you get herassed.