Which evidence below directly supports the author’s claim that while raising their children, parents will make mistakes?"Admittedly, that attitude is not without its benefits, but it goes too far in the other direction."
It's an inhuman task to make all of these decisions correctly."
"That doesn't mean we should stop trying to do our best, to make the right decisions whenever possible."
"We can take comfort in this much: we teach our children even when we're not trying to."

The evidence which directly supports the author's claim that while raising their children parents will make mistakes is the following one:

"It's an inhuman task to make all of these decisions correctly."

The author goes straight to the point: it is impossible to make the right choice all the time when it comes to raising kids. There is no school for that, only experience, and even experienced parents make mistakes while raising children they have later in life. It happens because every human being is a whole universe, and parents and their kids are not the same individual, which can cause conflict. It is in tense moments that parents might make serious mistakes, since they can get themselves carried away and act not according to reason, but irrational anger that makes them say and do things they will regret later. Even if they apologize, those impulsive acts can cause intense, or even permanent damage, to their kids' minds and personality. Nevertheless, all of it is only human. We have impulse and instinct, just like any other species.