I can not imagine a single group that will have no absurd and violent members.
Certainly not, but if groups actually want to be disassociated from their own vigilante terrorists, then the leaders of those groups have to do something about it, other than simply saying, we do not support... because that's seldom easy to believe.
And who are the leaders, in this case?
The 'organizations' making official public statements, in your original post.
So, following your logic, if this had been the good ole middle ages, the local priests in Sweden and England should have done something about the Spanish Inquisition?
Didn't realize that's what was being discussed, but sure why not, the queen led it, while the pope initially tried to stop it and then changed his mind. They were both influential and causational, but this isn't a situation of the Church being in a position of apposing a ruling government, so difficult to compare. The government isn't trying to prevent the Islamic church from taking a stand against their own extremist folowers. People in positions of power are the only ones with the power to do anything, except for maybe the general public turning vigilante and rioting in the streets. If organizational leaders aren't willing to lead organizations in the direction they publicly claim to be leading them, then it's left to the public to determine if what's being said is actually what's being done.