The problem is that makes it difficult bordering on impossible to have a successful protest.
As I understand it, protests work by putting stress on a system in order to force change. In cases where the protest overt actions such as police brutality or discrimination, it may only be necessary to provoke a response and then rely on the injustice of the response to apply pressure. E.g. when black people in the Civil Rights movement insisted on their rights and were met with violence it made it impossible for society to ignore the injustice of the system.
However, when trying to change policy or overall behavior it is often necessary to apply pressure by outlasting the other side. An example would be striking workers trying to outlast management.
Since protests, and social movements in general, rely on momentum, and constant pressure, kicking protesters out even temporarily undermines the ability to successfully protest.
is over a specific unjust action it may only be necessary to provoke a
It seems to me that for issues such as police brutality, discrimination, or unjust laws it's possible to have successful protests that are relatively short term. That is because the strategy is to purposefully to provoke a response that society won't tolerate (e.g. during the Civil Rights movement where black people would insist on their rights knowing that they would result in violence and thereby demonstrate the injustice of the system).
However, it seems to me that movements that o