Boycotts influence policy. It also makes me feel better. You buy whatever you want, I'll do the same. Every time I buy an I boycott a French product, it hurts that company. My little bit helps. The last time I checked, French import sales were down 10-15%. French tourism sales were down 20-25% from America. That hurts.
When I buy an American product INSTEAD of a French one, it helps that company, more American workers, and keeps my money here.