"What is wrong with people?" The answer is in the question: "people"
It was, is and will be a part of human nature to be curious. Some people realize, that with their curiousity they might infringe on other peoples rights or endanger them. In that case, they will control themself and move on.
Other people will not realize the impact of their behaviour. Arguments as "the area is so big and it is only my small drone..." or "I can go down if I see an SAR Helicopter..." or so will feed their opinion that there is nothing wrong in what they do.
Now, you might argue that "common sense" would bring people to realize that they endanger others, but "common sense" has to be build up by the environment someone is growing up in. What do I mean with that? Well an example.
My wife grew up in a family where it was completly normal to have campfires when they were hiking. As a young child, she was shown what to look for, what to avoid and how to jugde the place. Not only that, she was made aware that some clothing could be dangerous if close to a fire. Not that long ago, the kindergarten she works had a campfire. My wife told several children to get to a bigger distance, since they had these nice-looking "plastic" clothing. A colleague wondered and it was not until my wife explained what could happen, that she realized the danger. No one had ever told her.
TO transfer that to drone-flying people in and around emergency sites: If identified, they should be forced to participate in three or for mayor rescue actions so they can see why what they did is dangerous.