There is nothing unjust about being expelled from society when you are found to be too damaging.

What is unjust, though, is to be the victim of criminals who benefit from knowing exactly what the threshold is to not being removed from society.

Three strikes, in particular, is inherently unjust. There's no serious argument that it is not.

Silly fake faux-old-testament solutions like this don't actually work, as is demonstrated by the fact that most crime has fallen faster since they were abandoned.