Apparently I am going to throw my baby off a bridge

Two of Sam's favorite things in the whole world are cars and trains. This means that two of his favorite activities in the whole world are watching trains and watching cars. I had been reluctant to take him to the freeway overpass near our house, because it's a little noisy. However, a few weeks ago I took him to watch the cars, and it was just about the best thing he'd ever seen.

Before I go any further, I will point out that this overpass is a four lane street with wide sidewalks on each side, and a railing with bars. There are probably only 2 inches between each bar, and maybe 3 or 4 inches between the bottom bar of the railing and the sidewalk. The top of the railing is above my waist, and above Sam's head. The sidewalk is wide enough that two bikes can pass each other comfortably. The railing stretches at least 10 feet past the ends of the actual bridge on each side.

If we let him, Sam would sit there for hours and watch the cars. He points at every motorcycle, big truck, and bus that goes by, and people honk at him to say Hello. After we've been there a few minutes, Sam will often squat or sit on the sidewalk to watch. He holds on to the bars with his hands, and no part of him is on the other side of the railing. Today, he wanted me to be down there with him, so I sat down on the sidewalk and not too long later, he sat on my lap and we watched together and got excited about big trucks and I told him about all the cars.

We saw Justin ride by on his motorcycle, and he stopped just around the corner and came up to say Hi and watch with us. About three minutes later, a cop showed up. In a cop car. With his lights flashing. He asked if we were just watching the cars, and we said yes. He said that the police department had gotten SEVERAL CALLS and that people were extremely concerned. Apparently people have jumped from this overpass before (I've never heard of that happening, but I suppose it has), and that people were worried about the baby. WHAT THE HELL? There was absolutely NOTHING putting my child in danger in that situation, unless I was about to THROW him over the railing. I was holding him. There was ZERO chance he could fall because of the railing, and ZERO chance that he could wander into the traffic on the overpass because he was sitting on my lap a couple feet away from the cars, and I ALWAYS hold his hand when we walk down that street. He said we were not doing anything illegal but asked us to leave/go watch somewhere else because otherwise they were just going to keep getting calls. Is it really that weird that a kid would enjoy watching cars?

I am fighting back tears right now. I feel awful. I feel upset and angry and I think embarrassed that a copcar with flashing lights showed up, blocking traffic, to tell me that I was doing something wrong and people apparently think I am a terrible parent. I realize that this is not necessarily rational. I realize that some people (like my husband) could just say 'people are stupid' and laugh it off. But somehow I can't. I feel hurt and paranoid and self conscious. Sometimes, stuff just sucks.