Language and Moral Shock
There's an interesting concept called Moral Shock, originally coined by James M. Jasper, that explains how cognitive and emotional reactions within people, in response to particular pieces of information, may spur such an outrage in them that they recruit themselves into certain social or political movements, without having any preexisting ties to members or any information that would've led them to the movement in question. I suppose you can say it's the emotional and cognitive process that helps form spontaneous, grassroots movements, without the individual having the preexisting social connections that would've traditionally led them towards a particular movement.
Say you're sitting down watching a documentary on disproportionate amounts of animal abuse in a certain city, and you love animals. Seeing that documentary then encourages you to take some sort of action, to march on the streets along with thousands of others who felt the same way, or send an email to whoever is responsible or can punish the people who are responsible. Through moral shock, people actively recruit themselves and take actions by themselves, even in complete isolation from any other part of the movement.
Of course, the concept of Moral Shock, in itself, is not an inherently evil concept. Sometimes it's a really good thing that people can come together on a certain issue and make a uniform, yet completely unorganized push back. Like any other concept, however, it can be flipped around, with language (and by extension, imagery) being used as the vector for subversion. We've already discussed how certain words can illicit certain emotions, and sometimes actual reactions driven purely by those emotions. and
If I had to think up an example, I'd pull out the Mattress Girl shitstorm, particularly the part where after Mattress Girl started carrying around her mattress and was given the aura of Joan of Arc by the media, others started to carry around mattresses in their own campuses. Those who went to the same campus as her even helped her carry the mattress. All of those naive, young people came out in support of Mattress Girl because they heard all about her plight of being viciously raped by her lover, and her school throwing out her case, with neither of these things being remotely true. But it's the exposure of that information to those people that drove them, emotionally, to respond with support, and to recruit themselves in a loose sort of movement.
All of this occurs with words like "Rape" acting as bulwarks for the narrative in the face of factual evidence. People know rape is a terrible thing, and so it's easy to illicit an emotional reaction from them with an issue surrounding the issue of rape, hence why the mere accusation can destroy a person's life, even if he's found innocent.
Or you can take the recent witch hunt for George Hook and his comments on a particular UK rape case. The media and his own staff all called for his resignation for what they perceived as "victim blaming". He merely said that there is a certain amount of personal responsibility people have to take to ensure their own safety, and that includes not returning to random hotels with random strangers they met at a bar and barely know. Her rapist didn't physically overpower her or drug her, he simply convinced the gullible girl to come back with him, and she agreed. Any parent would tell their daughter not to do things like that, not to be trusting of strangers, not to inebriate themselves so severely that they can't function on their own.
The emotional weight behind an issue surrounding rape often drives the dialogue around said issue to be driven overwhelmingly by pathos, with little room for logic. The question of personal responsibility has no room to make its entrance because it's always interpreted as victim blaming. One's own sense of emotional morality often renders them unable to separate their strong feelings towards a subject from the critical, logical questions they should be asking themselves. The feelings behind an issue take precedence over the facts, the numbers, the statistics, or even the completely sensible questions and propositions. See any issue regarding Rape, Immigration, Race, or the Holocaust.
If you have any more examples of Moral Shock working to recruit people into social movements, please do share.