Hypothesis: the parent, by forcing themselves to sleep train, conditions themselves to ignore more of the infant's emotions; and the infant, observing no reaction to their emotions, learns the same behavior, leading to higher incidence of autism.

Typically (aside from some neurological disorders), there is an underlying reason for the infant to be crying. They could be hungry or wanting to urinate or defecate (many cultures begin potty training shortly after birth). This is frequent because their stomachs, intestines, and bladders are small. Figuring out what they want and responding is normal and has a long history of working, not just among humans but among all mammals with dependent young.

It's astonishing that some pop-parenting guide came along and said, "You don't have to figure out what the baby is crying about if they happen to be crying at night or if you are sleepy," and nobody stopped to wonder what night time had to do with it.