You're at a safety advantage in a smaller vehicle more often than not. If you're in an accident going fast enough for the size of your vehicle to matter, you stand a very high chance of getting severely fucked up no matter what you're driving. You need to not be in the accident in the first place, and driving a large vehicle with worse handling, longer stopping distances, and a tendency to roll over does not help.
Your average person is not mechanically inclined enough to assess the safety of vehicles, usually to the detriment of the safety of everybody else on the road. Another example of this is people's perception that they're safer with AWD in snowy conditions when all it's doing is getting the vehicle moving faster and giving the driver the confidence to push it way beyond its ability to brake in those conditions.
