Protestors, or at least people characterized as protestors, engaged in acts of vandalism and violence in Oakland. These incidents took place after a peaceful protest in the same city. Not surprisingly, the non-violent protestors disavowed these destructive actions.
Not surprisingly, people who are critical of the occupier movement might be inclined to point to the incidents in Oakland and take them as evidence that the movement itself is radical and violent. This sort of “reasoning” is, obviously enough, the same sort used when certain critics of the Tea Party drew the conclusion that the movement was racist because some individuals in the Tea Party engaged in racist behavior. It is also the same “reasoning” used to condemn all Christians or Muslims based on the actions of a very few.
To infer that an entire movement or group has a certain characteristic (such as being violent or prone to terrorism) based on the actions of a few would generally involve committing the fallacy of hasty generalization. It can also be seen as the fallacy of suppressed evidence in that evidence contrary to the claim is simply ignored. For example, to condemn the occupier movement as violent based on the actions of those few in Oakland would be to ignore the fact that the vast majority of protestors and protests have been peaceful (at least on the part of the protestors).
It might be objected that a group can be held accountable for the misdeeds of its members even when those misdeeds are committed by a few and even when these misdeeds go against the general views of the group. For example, if an employee engages in sexual harassment while on the job, the company can be held accountable for these actions. Likewise if an official engages in misdeeds while acting in her official capacity, the organization can be held accountable. Thus, it could be argued, the occupier movement is accountable for the violent actions taken in Oakland and these actions can be held against them and perhaps taken as defining the movement as violent and destructive.
In reply, the occupier movement is not, as of yet, a unified movement with an official leadership and official set of positions and goals. As such, treating it as an organization with a chain of command and a chain of responsibility that extends throughout the movement would be rather problematic. To use an analogy, sports fans sometimes go on violent rampages after events. While the actions of the violent fans should be condemned, the peaceful fans are not accountable for those actions. After all, while the fans are connected by their being fans of a specific team this is not enough to form a basis for accountability. So, if some fans of a team set fire to cars, this does not make all the fans of that team responsible. Also, if people unassociated with the fans decide to jump into action and destroy things, it would be even more absurd to claim that the peaceful fans are accountable for their actions. As such, to condemn the rather vague occupation movement as a whole based on what happened in Oakland would be both unfair and unreasonable.
If the movement becomes organized and develops a clear leadership, identity and so on, then it would be reasonable to start considering the movement to be an organization that could be held accountable for the actions of its legitimate members. However, until that happens the responsibility must remain on an individual level. As such, the people who did the damage in Oakland are accountable but the general occupier movement cannot have these incidents laid at its collective doorstep.
Also, even if the movement does become organized to the point that it makes sense to speak of group accountability, this still does not entail that the movement would be accountable for the actions of every person who claims to be a member of the movement or who claims to be acting on behalf of the group. This, of course, raises the question of the extent to which even an organized group is accountable for its members. One intuitive guide is that the accountability of the group is relative to the authority the group has over the individuals. For example, my track club has no meaningful authority over me and hence the other members have no accountability in regards to my actions. In contrast, my university has considerable authority over my work life and hence can be held accountable should I, for example, sexually harass a student or co-worker. In the case of a political and social movement like the occupiers, it seems unlikely that the movement would ever have a great deal of authority over its members and this would serve to limit the collective responsibility of the movement. Naturally, the same would apply to other political movements with a similar lack of authority (such as some of the Tea Party groups). This lack of substantial collective responsibility does not entail that individuals are not accountable for their actions-far from it.