A "Keystone Species" is a species that holds together an eco-system, without which the whole system may crumble. Naturalists may divide their effort to help save this other endangered species or that unique symbiotic relationship, but a more reliable and less labor intensive solution would be to focus their efforts on the Keystone Species.
Fox "News" is the Keystone Species of the eco-system of hate. They want us to run around dividing our efforts on all the different things they attack, when it is much more effective and less labor intensive to focus on the Keystone Species. If we focus our efforts on getting rid of Fox, the entire eco-system of hate will collapse.