Given that cemeteries are usually closed at night yet a popular target for vandals and bored teenagers I'm surprised more cemeteries don't have them for security. Then again, many cemeteries are quite large and game cameras able to make out faces are presumably not cheap. The cameras themselves sometimes get stolen, no matter how well they are secured.
Incidents like this I always wonder if it's actually some anti-Confederate protest/vigilante behavior or if it's just some troll/griefer. If you get your jollies by getting a reaction, making others angry or upset, Confederate flags and monuments are a really easy and obvious target.