If you read any other novel by Heinlein you'd see he's anything but a fascist.
Unfortunately most people are unable to find their way past the top layers of the book. Its why the 'intellectual' communities hated on it so much when it came out. It was hard for them to understand the difference between a 'police state' and a system of Capital Punishment where people actually were taught to take responsibilities for their actions.
If anything he was saying that our current system is terrible and spoils us, and that people in general could have a million times better system. If you notice they had just as much freedoms in the book (perhaps more) just the punishments for crime were a lot steeper. IE. being publicly flogged for stealing.
However the death sentence wasn't a closed doors event, but a very public shaming (for everyone) event, and his theory that such strictness in punishment would cause less crime.