At the cost of inviting controversy, there is legitimate argument as to whether Gandhi's insistence on the exclusive use of non-violent resistance worked in India's favor. To cite a prominent example, Gandhi suspended India's very successful non-cooperation movement (after tens of thousands of Indians had resigned their govt. jobs or dropped out of college to stop co-operation) because of one incidence of violence. [1]

In short: Rigid belief in the use of a single strategy is also harmful.

[1] http://en.wikipedia.org/wiki/Non-cooperation_movement