Probably a mistake to treat parenting styles as exogenous. Parents respond to their child’s temperaments too. It’s easy to be attached to an easy-going child. A kid that’s always crying is going to wear you out.
Perhaps a kid that is always crying is attempting and failing to communicate pain or discomfort.
I've been told that I was a miserable newborn--I cried nonstop for months and months and my screams made everybody around me miserable too.
My mother was told by family that I needed to cry it out, but 6 months on there was no difference. I was taken in to the hospital and was found to have had a hernia which required surgery.
After surgery, I'm told, I was absolutely quiet and unproblematic. Through the rest of my childhood and teenage years I was the 'easy-going' kid of the family. Through therapy I have learned that my attachment style is avoidant, and I have no doubt that this early experience (among others) heavily influenced the way I process emotions and feelings.
It isn't that I was a naturally 'easy-going' kid, or that I didn't have the troubles that my siblings had. I felt things, but my experiences taught me not to express them. I formed a tendency to over-intellectualize my experience and, in retrospect, heavily suppress negative emotions and even physical pain. My nature was not to seek out help when I felt immense pain, but to persist with self-reliance, at all costs.
Like the commenter above, therapy has done wonders for me in learning to recognize my feelings and having the capability in processing them in a healthy way.
I am not a parent and so I can't speak to the difficulty of a child's temperament; I have no doubt that one child's personality might be much more difficult to handle than another. A parent is clearly going to be affected to their children's temperament, but the parent is also responsible for teaching the child how to process those emotions, and is significantly more equipped in dealing with how the child affects them than the child is at dealing with how their parent affects them.
That's quite true. However, the article doesn't describe parents as such, it describes the actually style of parenting that took place, whatever were the reasons things went that way rather than another.