I agree that the intent and outcome is community focused, but the delivery is antisocial.
Its success is reliant on embarrassing a selfish individual or intimidating an ignorant individual. It doesn't necessarily educate the individual or give them an opportunity to defend their actions. It may cause them to reflect on their actions, but the objective is achieved through alienation rather than inclusion.
The individual circumstances will determine whether the ends justifies the means. I would be interested to know what other methods of protest you used and why they were not as successful.