I think in this case I'd say I support the act that makes it possible for people to claim back their land, and as a mediator my role is to help you to come to an amicable solution on how this will happen. But you as a mediator need to appreciate the thinking behind both sides. The mediator always has a measure of subjectivity, but there are ways to get around it. One way is to reveal your values that are premising the intervention. Secondly, as part of your preparatory work, become aware of your assumptions - about yourself, the intervention, the parties, and even possible outcomes that you might envisage.
Mediators seek to be impartial, but intervenors impact upon the intervention in a very definite way.
I don't think so. If the mediator has credibility, he or she does not have to subscribe to the values of any of the parties - but again, the mediator must make this transparent. Before that certain societies used to see violence as the number one means of dealing with conflict. More affluent societies are more likely to seek an alternative. The poorest of the poor, the illiterate and uneducated, because of lack of better understanding and better strategies, often resort immediately to violence.