You have power as a consumer, but only when you use all your resources. It’s important to think about who feels better from your personal boycott: the child you aim to help, or yourself?
Gandhi incorporated this idea through the Hindu principle of satyagraha, which memorialised the Indian Independence movement as one of non-violence. However, there were a series of specific conditions in India that enabled the movement to avoid violence, conditions that definitely don’t exist in most oppressed communities.