Sure they would, if the reason for the firing was based on race, sex, religion, etc. But they weren't. They were fired at best for criminal activity and at worst because they were conservatives. Neither one is a protected class.
There is another principle which protects employees from exercising a legal right, such as “the right of the people peaceably to assemble, and to petition the Government for a redress of grievances.” Of course the employer could claim that the event in DC led to some illegal activity, but firing someone for supporting someone politically leads to a system like communist China, social media and all.