Why do those who bear the costs (higher milk prices or taxes to support the maritime industry) not oppose these sorts of policies? Would it be rational to oppose them? Would it be rational to know about them?
It would be rational to know about them. But people who bear the higher costs may only be slightly affected and find that the greater good is served by higher taxes.
Think of schools. Fortunately every citizen can vote on funding for schools, whether they have children in school or not.