"Terrorism" means an act intended to intimidate or coerce a civilian population, or to influence the policy of a unit of government by intimidation or coercion, or to affect the conduct of a unit of government, by shooting, throwing, launching, discharging, or otherwise using a dangerous weapon at, into, or in a building, vehicle, airplane, railroad engine, railroad car, or boat, occupied by another person, or within an assembly of people. The terms "intimidate", "coerce", "intimidation", and "coercion", as used in this definition, are not to be construed to prohibit picketing, public demonstrations, and similar forms of expressing ideas or views regarding legitimate matters of public interest protected by the United States and Iowa constitutions.