The reason the FAA had to get involved is basically because people were illegally using drones for commercial purposes so they needed to put something in writing to try to keep up with modern technology. The other aspect is obviously a safety issue. Flying a drone around in your backyard probably isn't going to hurt anything (ignoring the whole privacy issue anyway). But taking something that can climb to 4000ft with a camera strapped to it can cause some serious issues.
I remember one time when my brother in law was flying a RC helicopter outside for the first time... he started to fly it around, climbed higher than he was comfortable with, and just said "Uh oh!" and handed me the controller. Not a problem in that case, but what if something similar happened to someone flying around out of their line of sight and they see a regular plane coming towards their drone on camera? Whether it's a little Cessna landing on a grass strip, a crop duster or traffic plane flying low, or a commercial airliner on final approach you can't just say uh oh and drop the controls - there's a chance that someone (or several people) will die. And that's with a responsible person that just doesn't know how to react to a given situation. Imagine what happens if someone is intentionally trying to be a smartass or just outright maliciously trying to cause harm?
I guess I just look at it kinda like I look at lasers pointers. Lasers that were once large, bulky, expensive, and basically limited to corporate offices and laboratories got smaller and cheaper to the point where everybody could buy one at their neighborhood gas station for a couple bucks. Then people started thinking it would be funny to go out and shine them at airplanes. It's not funny and it became such a serious issue that you will now be fined $11,000 if you do it and get caught. And people do get caught... gotta remember if you're shining a laser at a plane you're basically pinpointing your exact location and you better believe ATC and local police will be notified.
I know it probably sounds like I'm anti-drone but I'm really not. The idea of having a camera strapped to something that can fly around with ease is pretty damn cool. I remember years ago when I flew RC planes and helis how cool it would have been to be able to do just that but the cameras were too big and/or too expensive at the time. Times change, technology changes, and it does so quickly... possibly too quick in this case. Aviation sure has some a long way in 100 years hasn't it?
Buy your drones and have fun, just do so safely and legally.