Yes, I completely agree that deadlifting is 100% natural. We have hands to pick stuff up. Stuff is on the ground. We deadlift to pick it up. We've been at this for millions of years and our bodies are made for it. We do not squat to pick things up. We squat to crouch down when it's more convenient to do that than to sit on the ground. We are made to pick up lots of stuff repeatedly, like a deadlifting exercise, but squatting up and down, NO! That's silly movement! Actually, I don't think there was much one could choose to squat with before the barbell was invented. Large rocks and similar are not good for squatting with - sitting upon, yes, but holding and squatting for no reason - no.
This is why it's hard as heck to do deep one legged squats - we aren't made for them. We can easily get down about half way, which is all we need for hiking, running, jumping and walking, but getting lower we feel that something is quite amiss and it takes special training to do. This is also why they're great exercise! They force the body to do harder stuff than is natural.
It's like with pushups - we have the ability to pick our upper bodies off the ground by pushing down with our arms, but with one arm - no - we're not really made for that. This is why it's such awesome and superhuman exercise to do it.
I'd think that the more natural an exercise is, the less valid it is for building superhuman strength.
Think about walking - putting 100kg (in my case) on my right leg, then left, then repeated tens of thousands of times. WOW! What pressing and endurance power!!! Every fat, weak, blob can do this!
That is something natural our bodies are made for, that's why.
Now, take a one arm handstand pushup. This is a ridiculous, useless movement that we have no need for in nature. This is why if you train for and can do it you're a jacked "mutha"!
Computers aren't natural, which is why they're useful. Cars aren't natural, but they're useful. Kettlebells are ridiculously unnatural things, which is why they're useful.
We make natural movements like walking and deadlifting unnatural, and therefore useful for developing unnaturally great amounts of strength and endurance by loading our bodies with unnaturally heavy weights. This is taking a natural movement, which is not going to challenge our strength systems, and making it unnatural by making it ridiculously and unnaturally heavy.
Natural is bad.