Vanunu was released early on parole as a form of leniency and mercy and he has continuously violated the very conditions HE agreed to. In the US Parolees for example cannot leave the state with out permission and if they do so they are arrested and put back in prison. it's called the law.
Donald Trump: Israeli settlement construction in West Bank should 'keep going' (Haaretz)
from the article: 'Shame on you, democracy,' Vanunu yells as he returns to prison