"No employer shall coerce or influence or attempt to coerce or influence his employees through or by means of threat of discharge or loss of employment to adopt or follow or refrain from adopting or following any particular course or line of political action or political activity."
Perhaps publicly criticizing the company you work for does not qualify as a political activity? But expressing support for or opposition to a candidate, law, or public policy presumably would. A company would presumably not be able to fire you for attending or expressing support for a protest or political rally.