Low-level coercion can have high level effects. Coercion doesn't have to be at the national level, either. Most elections aren't at scale, and the ones that are, are decided on a relatively few elections around the nation.

Coercion doesn't have to take on the form of violence, social and financial reprecussions can be incentive enough to vote a certain way with the proof that you did.

Think about this: "I don't want to associate/hire/do business with anyone who voted for Candidate X or Referendum A"