The bias is strong with this question. You seem to be implying that there is a more efficient way to meet the needs of a cause. Do we need another burger restaurant or bar? Couldn’t we be using our money/energy/resources better if we all got behind one chain?
The reality is that a variety of nonprofits addressing an issue is a good thing. Different leaders and teams will have different skills/perspectives. That will lead to them addressing issues in a unique way. These are complex issues that are to big for any one approach to work. Just like people have preferences to the best place to get a burger because of taste, ambiance, and price. Having multiple nonprofits focusing on similar/same issues allows there to be collaboration, perspectives, and more attention given to implementing solutions. Some of which will work, and some won’t.
There is also no way to directly ‘support the cause itself’. Every cause has logical, organizational, relationship, institutional issues that must be engaged with. In a kind of platonic idealism you could fix the world simply by applying the right tools in the right way at the right time. Yet thats impossible in practice.