I don't think this is accurate. The defense strategy is why most things don't attack puffer fish, sea urchins, or trap door spiders. Defense does not mean the turtle strategy, it means using your defense as such a costly prohibition to attack, attackers don't bother. 

It costs very little to make a chicken wire dome around your house that would stop most drones. If drone assassination is a REAL and present danger, no one would walk around without identity obfuscation. Rubber masks cost less than a drone bomb. Uniforms cost less than drone bombs.

Here's the equation: 
Attack = X
Defense = Y

If cost of X > Y, defense wins.