When I qualified as a mediator (in January 2016) a colleague explained that in virtually every single dispute he had mediated, the event that the parties had initially regarded as the cause of their conflict turned out to be a secondary cause.
This has been my experience too. It is necessary to get to the root of the problem in order to help mediate it. The mediation process enables the root causes to be identified, and helps the parties overcome poor communication, misunderstandings, assumptions and a multitude of other barriers to negotiation and resolution.
For example, in a workplace case the new owner of a fashion shop started a disciplinary procedure against the manager (who she had acquired with the business) for apparently trivial matters. The manager lodged a grievance that the new owner was treating him less favourably because he was gay. These hostile HR procedures were having a damaging impact on the day to day working of this small business. Eventually, it transpired that the real cause was the manager’s resentment that the previous owner had broken his promise to give him (ie the manager) the opportunity to bid for the shop before selling it elsewhere. Once this was out in the open, the way was clear for the owner and the manager to build a working relationship.