As much as people may be willing to mimic the behavior and appearance of others in order to fit in, secretly they often envy those who show intentional dissent. According research we admire the person who has the guts to do what we dare not do–challenge group norms–as long as the person is not challenging our own norms.
“Indeed, people may speak up and dissent from important group norms not because they want to be difficult and destructive, but because they care for the group and its future.” 
The heroes of novels are often principled rebels, not lacking in loyalty but willing to speak up against those with power for the benefit of the others. In the world of fiction, the hero often sways the fence-riding group to abandon the person doomed to be the villain by the use of stirring altruistic words. And, sometimes the hero engages in a knock-down, drag-out physical fight, too. But in real life? In a true uphill struggle by the minority to voice dissent and influence the majority, the rebel with a cause must be consistent. Consistency is not necessarily the hobgoblin of small minds.
Group dynamics affect the challenge of being a real-life rebel with a cause. Social groups tend to seeks consensus so that everybody can get a long. Even if this consensus is not rooted in reality, the fact that everybody else holds the same opinion provides enough validation for most people. They have committed themselves. They don’t really want to hear some one who questions their ideas. If you question the consensus, you run the risk of being excluded. If you back someone who is asking the difficult questions, the group may exclude you, too. 
Persistence on the part of the minority is their major weapon. The majority group starts with the assumption that the rebel is not correct but the persistence on his or her part creates a conundrum. ‘How can they be so sure and yet so wrong’?  If the rebel view is going to have any chance of gaining a following the supporters must remain consistent over time. If sticking to their guns is seen as attention seeking, or a rigid belief rather than consistency, it will fail.
Also the rebel with a cause does not have the luxury of both ‘winning friends’ and ‘influencing people.’ Rebels may influence others by remaining adamant in their position, but most people will not like them. And, the rebel hero must remain strong when punished by the status quo. An attempt to gain support through appeasement is typically seen as giving in. If the rebel gives in the chance to influence others goes down the drain. 
Basically, the uniform view of the majority is never as solid as it appears. Most people are conformist as they fear exclusion. They try to appear to adopt the majority position even if they privately disagree with it. But, timing is everything when trying to convert private dissenters into open rebels. The hero must speak up before members of the group have a chance to follow through with any action based on the mistaken belief of the majority. When people comply with group demands, and then someone criticizes the beliefs of the group, they do not climb on board behind this person. Rather they take the criticism personally and preemptively reject it.
So it is those fence-sitters still clinging tightly to their fence that are most willing to admire the person who dissents for principled reasons. When the rebel with a cause voices an opinion that they secretly hold, they might slide off the fence in his direction, with a sense of liberating relief that they have done the right thing .