(First of all please forgive me for my mistakes, english is not my mother language, but I'll try to express myself the best I could)
I would like to tell you that all of your points are valid. They are true and right problems and you have a very good eye to search for a solution, BUT.
You should understand that the Naruto is not happening our real world, in our days. It's a fantasy world which uses the basics of the traditional medieval Japanese culture. And the traditional Japanese culture DOES involve children as soldiers (but it's only a matter of fact, because back in those days 12-14 years old boys did not count as children). Moreover the Uchiha massacre WAS tragic and terrible, but unfortunately it's totally fit into the picture if we are talking about medieval Japan. Also fights till death was a very real thing in every community based on military forces back in those days. It's cruel, but it was real.
Japanese culture also really strict and careless about the families, everyone has the rigth to foster their children the way they want, no one had the right to speak up for them. Family is a strongly closed community, it was none of anyone's business what happened behind the closed doors. Yes, they did abadoned children by skills, they did choose favourite ones, and they did abuse the weaker kid. Yes, it's cruel too, but it was their reality. Apparently Kishimoto created a very realistic interpretation for the real world's clan system.
Please understand me right, I does NOT say that it is alright, but it is a part of the culture and the era what Naruto (aka. Kishimoto) uses. I understand your anger and dissapointment, but you need to see that there are culture differences, these are the things that make Naruto what it is. It's a world based on military state system, and a military state is not a kind or caring one.
Also the japanese culture is one of the most strict one around the world, they are really closed in the field of emotions. They doesn't have the culture of theraphy or talking about traumas, it's just not a part of the picture.
I totally understand your feelings, and you are right in the most points, but you should consider that Naruto is a greatly different culture and world than yours, and there are reasons why the characters act like the way they do. Japanese is a very different culture for anyone else, but it has always been back in the history too - they don't understand us just like we can't understand them. :)
Moreover we can clearly see some signs of improvement in Boruto - in the chunin exams those fights were totally safe, they didn't need to go into a highly dangerous area, or they didn't have the pressure to kill if its needed. It was a familar spare match, and that's how you could measure the powers in the field of martial arts.
Of course there is a long way to go, but for a japanese culture based manga, Naruto improved pretty good in Boruto. Of course there are huge bullshits (like Orochimaru is a free man or the orphans), but they are the little faults in Naruto, the little stupid things every manga has.
Yes, Naruto has a bunch of idiotism in it, but the tasks you pointed out are the part of the world structure, that's why people loved and bought this manga, because it showed something new. No one ever said (not even Kishimoto) that the ninja world is a kind one. It IS horrible and cruel in a lot of apsects, but that's what made it realistic.