How do you know squatting has more wear and tear on bodyparts than bending over? We both don't have evidence to back up our claim, so both of our opinions are just that..opinions. My opinion comes from this: it just seems that why would a baby have ingraved in their brain to squat to pick something up. It's their instinct, like it should be that way and that's why they do it. It's instinct to cry, etc. Humans weren't supposed to sit around for 8 hours a day and grow to have inactive glutes with tight hip flexors, we were supposed to be up and around searching for food for our family. That's the way I think of it. Our bodies evolve to become the fittest it possibly can be to our environment.
Yes it may be easier to bend over, and you may only use a fraction of the energy to bend over, but the "easier" way is not always the best way... for example.. Why squat below parallel when you can squat above parallel since it takes less effort? But then the easier way puts more stress on the knees unlike the safer, "harder" full squat.
Also, think of it as repetition. Do body weight squats to continually pick something up. then bend over to continually pick something up. Your back will start to hurt from the bending over. I can relate to this because I used to have a job where I had to pick things up all day. You can only bend over so much but squat all day.