It is. Anyone who understands probability knows this.
I'd counter that anyone that understands probability would agree its isn't a 'scam' by insurance companies. Non-fault accidents are not a 100% random event.
The chances of someone running in to you (assuming you do nothing to cause confusion yourself) remains the same. Only the one at fault is more of a risk.
You touch on the reason without realising it - 'assuming you do nothing to cause confusion yourself'. There are numerous examples of situations where driving style can contribute to the occurrence of a non-fault accident. This doesn't make it the innocent parties fault - it just contributes to the chance of it happening and therefore means that not every driver has exactly the same risk of being involved in a fault accident.
Here are some examples of legal driving behavior that might increase your chance of being involved in a non-fault accident:
a) Always parking on the end of a row in a carpark - more chance that people might clip your car. Not your fault, but your choice to park there increased the risk.
b) Late braking. Most people drive only in accordance with the car directly in front of them, if you see a line of stationary traffic and brake quite sharply and lately but safely stop, an inattentive motorist behind you may not react in time. Their fault, not yours, but your choice of braking style has contributed to the situation.
c) Parking on the corner of a road at the bottom of a hill in icy conditions. Legal but you shouldn't be surprised if you come out to find a halfwit embedded in the side of your car.
d) Accelerating swiftly off the lights as soon as it goes green. This increases the risk of being hit by a moron who screws up an amber-gamble
e) Not giving way to tools flying down the sliproad trying to force their way onto the Motorway. You don't have to give way - its your priority! But those who rigidly enforce their priority might find themselves more likely to make contact with the 'don't look and expect everyone else to move' idiots... again, not your fault, but if you'd have eased off and shook your head at him it may not have happened..
etc etc
None of these hypothetical examples put you at fault but they are all examples of situations where choices made by the non-fault driver has increased the chance of being involved in a non-fault accident.
We all know people who seem to have been involved in quite a few non-fault accidents and we all know people who've never ever had one...