What was good about raising Spartan boys?

The upbringing of boys in Ancient Sparta was aimed at making them great warriors and athletes. Therefore, the main focus was on physical fitness. They grew up strong, dexterous, hardy. And this, of course, is not admirable. But people with physical disabilities, weak, sickly disgusted the Spartans and were considered second-class people. When such children were born, they were immediately disposed of. And this is completely unacceptable for a modern person.