"to punih him some more for an horrific previous crime he has already been punished for"
No, he hasn't really been "punished" for anything. He has been kept aside and (hopefully) rehabilitated, and set free with the understanding that if he steps out of line, he WILL get the punishment he deserved and only escaped because of his age.
The paragraph below is from your link on secure children's homes. It reads like the normal day in the life of a child in a normal family - get up in the morning, breakfast, school, activities, computer time if he's been good. Basically, state has taken over his education and social conditioning, since his family have failed so spectacularly.
?We get up at 7.30, Breakfast at 8.15. Then chores ? hoovering, dusting ? till 8.50. Then education, with lessons till 12.15, including a short break, and then lunch. Then education again until 3.30, after which there is some individual or group work till tea at 4.45. After that it?s homework for an hour... then after that Structured Activities ? craftwork, model- making, gym, badminton, table tennis, volleyball,? says the manager. ?Then after that maybe some time on the Xbox, if you?ve earned the privilege. We have supper at 8.30 and then it?s off to bed with everybody, depending on their age, locked in by 9.30.?
That sounds like life in a normal family. With activities, school, computer time if you've been good.