There are many ways that a citizen of an imperialist nation who is not allowed to protest freely might express dissenting opinions. Some options might include:
1-Writing letters or articles for publication in local or national newspapers or magazines, or publishing on social media or personal blogs.
2-Participating in boycotts or other forms of economic activism, such as supporting businesses that align with their values or divesting from companies that engage in unethical practices.
3-Using art or creative expression to communicate their views, such as through poetry, music, or visual art.
4-Participating in more subtle forms of resistance, such as spreading information and ideas through word of mouth or using code words or symbols to communicate with others who share their views.
5-Seeking out and supporting organizations or individuals who are working to challenge the policies or actions of the government or other powerful institutions.
It is important to remember that expressing dissenting opinions and challenging injustice can be risky, and it is important to be mindful of one's personal safety and the potential consequences of such actions. It may be necessary to be strategic and creative in finding ways to safely and effectively communicate one's views and push for change.