#1. No, actually the crud is to blame. Last I heard, humans didn't have telekinetic power to dictate where debris goes when a gun is fired.
It is the user's responsibility to do the maint. needed for the gun to function properly. No, we don't have the power to dictate where the debris goes, but we do have the power to clean it and even the power to chose an ammo that doesn't give us enough crud build up to be a problem during a course of fire.
And we have the power to learn approximately how many rounds of whatever you are using, that you can fire before lack of cleaning and/or lube will cause a malfunction. Few people do know, but that doesn't change their responsibility.
#3. How do you define crap ammo? I had a gun jam up on Lapua ammo. I don't consider Lapua crap ammo. Maybe you do. And yet, the gun didn't jam with Wolf and Tulammo. Does that make them premium ammo?
Aside from obvious physical defects, my standard for defining "crap ammo" is the same one the gun used. if it doesn't work in my gun, its crap. Doesn't matter who made it or how much, or how little I paid for it, if my gun won't run it, then for that gun, its crap.
And some guns are more picky than others about what they like, and what they don't. The pickiest seem to be rimfires, but centerfires have their quirks, too.
A gun that is sensitive to crud and ammo is not neccessarily operator error. Some guns can go thousands straight out of the box with no lube, no break in, no maintenance, no cleaning.
I disagree, to a degree.
if the gun won't go "thousands of rounds" without lube, cleaning and any other required maintenance, it is the operator's responsibility to know that, and do the work needed to prevent failure. This is one of the things that should be learned during practice and training with your gun and ammo. Its more than just being able to get rounds on target in X amount of time. Its also about learning how to operate and care for the gun as you do it. Learning how to do things to minimize the negatives inherent in every mechanical system.
Learning how to work the gun so it works its best. In a way its like learning a standard transmission, getting the feel of the clutch, etc. There are several different ways one can operate it and shift gears, but some methods of operation are better than others.
Different cars and trucks have different "sweet spots" where things work their best, and so do firearms.
One time I found a .22 Luger at a gunshop. Gun looked 95% or better, but was priced well below usual market price. The shop owner was looking to sell it because he had briefly used it as one of his range rental pistols, and it was a "jammo-matic" so he was offering it at a discount.
I bit. Took it home, and sure enough, it jammed every 2-3 rounds. Then I OILED IT. Surprise, surprise it ran flawlessly through the couple hundred rounds I shot after that...and, its worked ok ever since. It just needed a little proper care and attention.