I contend that another reason is that electricity doesn't blow things up nearly enough.
We've all see people smoking at the gas station, fueling a running truck, sticking their hand in the elevator door...and the fire/explosion/amputation don't happen.
If every single time someone pumped gas with a cigarette in their mouth the hazard would be taken seriously.
Folks figure that electricity is safe so long as the electric doesn't go from the wire to somewhere that could cause a problem. Generally whatever gets cobbled together kinda works.
When nothing bad happens the perception of electricty causing fires goes down to 'can cause fires' to 'might cause a fire' to 'rarely causes a fire' to 'almost never causes a fire'. They forget that 'almost never' is comparable to 'virtually unsinkable' and we all know where that went.