What you’re describing is administrative detention. Don’t like administrative detention? Take it up with the Fourth Geneva Convention, where it is explicitly permitted under Article 78.
And let’s not try to equate “children” like Marah Bechir and Kfir Bibas. Marah Bechir was tried and convicted of stabbing a policeman when she was 16. She was sentenced to 8.5 years. Kfir Bibas was a 9-month old baby that Hamas kidnapped and either killed or allowed to die. Marah Bechir will be released in exchange for 1/3rd of a civilian hostage. She will be lauded as a hero in Palestinian society when she returns home.