After long observation, I've come to a conclusion about something. The problem with any social movement aimed at remedying a perceived problem is that the leaders will tend to be the people most passionate about the cause. And the reason they tend to be the most passionate is because they're the ones who have been most harmed by whatever it is they're trying to change. The more vocal and committed the leader, the more likely they are to have been seriously traumatized by whatever it is they're fighting.
The problem is that they're also the people least capable of maintaining a sense of perspective about the problem. They become radical extremists who see the issue as black-or-white. They're difficult to reason with. They're nearly impossible to negotiate with. They're prone to making abusive statements about those who disagree with them.
When you've got loud, brash, unreasonable people leading a group and being the personalities the public associates with it, the group and its message tend to lose credibility (unless their views are widely accepted enough to become mainstream). Moderate people who would otherwise support the cause therefore feel alienated from it and make a point of identifying as not being "one of those crazy people over there." Moreover, if there is an opposing group, it will cite quotes or actions by those leaders to discredit the entire movement and its goals. In this way, the people who care most about the cause end up being the chief reason for its failure.
A wisely managed group, then, should be one where the radicals are put to work as foot soldiers, willing to sacrifice their reputations to the cause, but never allowed to ascend to positions of leadership or where they become the public face of the movement. The leaders can then maintain both an agreeable public image AND plausible deniability about the actions of their radical operators.
The problem is that if these people don't feel appreciated by the movement, they're highly motivated to go off and form their own organization, drawing all the radicals away from the more socially accepted parent organization. Call it "radical distillation." An example that comes to mind is the Tea Party. The GOP recognized the necessity of maintaining control of radical splinters like this, and to do so, you have to absorb them and offer them a sense of being more appreciated and more in control. That sense can be an illusion, but it must be present, or the radicals will continue to go their own way rather than serving the leadership of the larger organization.