I have many politically and socially active friends and I really respect them.
They post on social networks, talk to people, organize conferences etc and I respect it too.
The problem is... It's all pointless because the target audience is being chosen wrong.
Let me explain.
If you're a gay rights fighter, all your facebook friends are probably gays or gay friendly people. Homophobes don't go to LGBT conferences so you'll never be able to change their opinions.
The same with racism. Do you have any neo-nazi friends? I don't. All my friends are pretty tolerant and respecting other people.
Or my lovely socialistic friends. All the people who read you are already your "comrades", they don't need to be convinced in anything.
Identify your target audience or don't waste your time.