This is where arguing that you can fire people for political speech will lead

Depends on your company policy. If the employee missed a scheduled day off of work that would be grounds. LIkewise, if the employee wore a company uniform, on or off duty, that would be grounds for dismissal. The problems I see are that the men that were fired could sue their employers for lost earnings and legal fees, as long as they weren't scheduled to be at work but will probably prefer to let the incident slide into oblivion. They have a constitutional right to freedom of expression. personally, though, I think they will lack the fortitude to do so, as the resulting trial could anger locals enough that they will become open targets for members of the radical left.

There are many articles on this incident right now that say that first amendment protections don't protect against these types of fireings. (Basically the "these guys got what they deserved" attitude).
However I might not like these guys oppinions, the idea that one can LEGALLY be fired because they express a position or engage in political nativity that their employer dissaproves of is scary. What if I'm an employer who disaproves of comunism/socialism. Can I fire you because you attended a pro-Bernie Sanders campaign. After all, if we permit these firings on the grounds that the first ammendment does not protect you from being fired for political speech, we have set that precedent.
Of course it's different if you're a major representative of your company (i.e. public relations), but for menial positions, it is ridiculous.

We are on the same page. I'm so far to the left I make Bernie look like a Tea Party Patriot. I don't have to agree with what they say, but I'll defend their right to say it. These are not employees with a contract. at the most, an employer should be allowed to put a controversial employee on paid leave until the furor dies down, covering the employer's ass and not infringing on the employee's rights. I say a lot around here that gets the hackles of the alt right, but my experience shows me that if I look beyond my personal feelings, and try to see both sides of the issue, I can make an honest decision. constitutional or not, their firing does not meet the requirement of being discharged for just cause. This is a situation where low level employees have been axed by participating in a legal rally. I do see some reverberating repercussions not only on the businesses that are involved, but also on the SJW that provoked the firings.