Have you tried recruiting isis? 

 Why? Activists want to reach people. They need to go where the people are, their job is to reach people and tell them uncomfortable truths.

Silo'ing yourself can allow you to say whatever you like, but so can messengers with groups. Preaching to the choir is not as useful as reaching the uninformed.

But hey, if they can convince others to come to them, then they will make it somewhere they love.