You're wrong. Very wrong.
They're all different. It is a minority, yes, but some babies do prefer to fall asleep on their own.
I suspect part of it is that it feels so unnatural to do it that no one really does it. Plus we're pretty much told not to do it nowadays, so how do people know what their baby will do if they don't try it?
When DD was about 6w old I was on my own with her one evening and she just would not go to sleep - she wasn't crying, but she'd almost fall asleep in my arms and then her eyes would pop open the moment I put her in the crib. I was so tired and so hungry I nearly snapped (not badly, but I put her down once too heavily) so I left her in her crib in the dark and walked away for 5 minutes, as you're told to do.
And then when I went back a few minutes later, she'd fallen asleep herself. And so we did that every night from then on. (Yes, committing another MN sin of the baby being asleep in another room for a few hours.) For naps she needed help, but come 8pm she just wanted a dark, quiet room and slept so much better than she ever did trying to fall asleep in even a dim, quiet living room with us.
She rarely cried during the day either, unless she was starving, and then that was easily solvable.
All babies are different.
But why on earth would you just assume that your friend is lying and, basically, accuse her of neglect because her baby is different from yours?