If knowing your customer strategy works well, then the world would be much happier place to live because then we won't get any automated adverts on mobile etc. I understand your point, but imagine, a recruiter planning to call you only to ignore it thinking 'Oh, s/he a busy person. Let me not disturb s/he'. Not going to work in real world.
'Knowing your customers' usually means that sale-person know how and what a customer is thinking so s/he can bank upon it. It doesn't mean that sales-person should contact only when customer is away from work and is not too busy to talk.
I share your exasperation and agree that while I hold back such emotions, sometimes I am tempted to reply back in a bit offensive manner. And I have never replied to any such mails in past, not doing it in present, nor I am inclined to do this in future.
But I cannot agree with your second point in Additionally section. The recruiters are doing their jobs, whether or not just sending cold emails. They are not obligated to understand or even know the 'work style of engineers'.
Is there a way to add the stress/elasticity factor to it, so as to demonstrate that after certain point of pulling a point on cloth, any more force will tear the cloth?