'Nailed' seems to me similar to 'trapped'. It is a painful loss of freedom. It has to be imposed. People get trapped through a loss of freedom by all sorts of things. They get 'nailed' by life. I am not quite sure what this has to do with the crucifixion of Christ. But, somehow there is a connection. In a dialogue with his sufi Muslim neighbour Christian de Cherge has clarified for him the three crosses present in the crucifixion.
'Which one comes from God?' Christian asked him
'The one behind'
'Which is the oldest?'
'The one in front...God had to create the first one before man could make the second one'
'What is the meaning of the cross in front,
of the man with his arms extended?'
'When I extend my arms', he said, 'its for embracing, for loving.'
'And the other?' I asked?
' The other cross is an instrument of hatred, for disfiguring love.'
The third cross, the conversation goes on to clarify, is the journey that people make to separate themselves from the cross of evil behind them to bind themselves to the cross of love in front. It was love that bound Jesus to the cross. It is love which frees people from entrapment. It is love which draws people through the stations of the cross - otherwise, what would be the point?