It is also known as kidnapping. These protestors are violating the civil rights of everybody whose free passage they are blocking. Here it is in the UK but BLM and Antifa committed this crime all last year.
I wonder if these people could be held (and BLM and Antifa) financially responsible for loss of income, or pain and suffering, and any number of other recourses available if we don't want motorists taking the law in their own hands while protecting themselves from false imprisonment.
Authorities need to do their job or society will devolve into mob on mob violence.