A person may be so successful at practicing deceit upon the others, but no human being can lie his own conscience. A dictator may be able to hide behind a fortress and can escape from the attack of the enemy, but he cannot avoid the attack by his own conscience and guilt. It is the way non-violent pressures can be brought to bear on the military dictatorship. Although the non-violent pressure can be effective in certain ways, such pressure cannot normally be expected to brought concessions on fundamental issues. This is because of the way a dictatorship is different from normal politicians.
Politicians are open to reasons and listen to the differing views as much as possible.
Military dictators will certainly be shakened in their minds by these non-violent protests, but still, will not make concessions. Secondly, these non-violent actions by the support groups help the oppressed as they lend the solidarity. These non-violent actions are also the best way to maintain the momentum of and solidarity within the movement. I always remember, for example, a protest of NGOs in 1993 at a UN forum in Geneva. I personally feel much gratitude towards those such people, and certainly their action encouraged me to be more involve in the struggle.