While most of the groups have a basic cause that is palatable to the majority of the populance, i.e. be nice to animals, freedom and justice for all, the fringe groups within them overwhelm the rank-and-file because of the energy and resources they expend to further their specific agenda. The moderate rank-and -file members then leave or become mute due to their perceived disenfrancaisment and allow the takeover to happen.
The best way to oppose this, is to use the tactics of the left. Join the groups then dissent at every opportunity. Hold these groups accountable in public forums such as newspapers, TV "comsumer activist" programs wherever. It worked for them why can't is work for conservatives?
If you say it can't be done, look at what happened to the Red Cross. They were untouchable until the truth came out.
Amnesty is at the forefront of promoting racial disharmony and ensures that the new black immigrant population will grow up to hate the white man.