A feeling of brotherhood should be propagated amongst the masses.

Propagated in the given sentences would mean to spread or promote. 

Among the options disseminated would be a synonym of propagated rather than opposite. 
Dissipated means to scatter, which, although it carries a negative tone, still carries the same sense of spreading the feeling of brotherhood. 
Crushed means to completely destroy something, and while this, too, would fit the context, it is not the opposite of propagating. 

Suppresses would be the accurate opposite here, implying a stop or trying to stop the spread of this ideology of brotherhood. 
Therefore, Option B is the correct answer.