Also it seems like these small planes have a lot of incidents, I'm guessing due to relatively inexperienced pilots?
There's also less redundancy in the plane overall so if something goes wrong it's more likely to lead to serious issues. A large commercial plane has multiple pilots, engines, power sources, control surface systems, computers, sensors, etc.
A microburst could easily take out a full-sized airline at low altitude. That’s why airports and planes have equipment to detect air shear so they don’t fly into it. Small planes are far more affected by weather and don’t typical have radar or safety systems like flight envelope protection.
But the free-form nature of the vehicle operation provides more opportunity for screw-ups. Maybe someone was buzzing his house or not paying attention to flying while giving a sightseeing tour to his friends.
Compared to commercial flights, it's no wonder that GA has a far higher accident rate. Commercial flights fly extremely predictable and repetitive routes and procedures, which reduce the number of variables into the mission. I'd liken the comparison to that between personal cars and buses, except commercial air travel is even more regimented than bus travel.