1) The societies of the world are composed of individuals. Individual actions, if appropriately cultivated and communicated, may become group actions. Individual actions absolutely matter.
2) At no point did I claim to be against trade.
Encouraging people to not buy stuff from an entire country or do business with them (basically an informal boycott) sure sounds like a way of penalizing trade, but much less effective. If that's not what you meant, maybe explain it again?