If, for getting into an argument with certain people, you can be punished with being ostracized, fired, prevented from earning a living, demonized by the news media, and put through a years-long wringer in the courts, your freedom of speech is harmed even if at the end of it a judge says not guilty.
…and if you force people to be in your company regardless of what you say does to those people, you've taken away their freedom of assembly.
Not everything that's legal is right. A company that fires someone because they got in a Twitter argument on their own time is behaving legally, and an attempt to make such an action illegal would probably cause more problems than it solves. But a company that does such a thing would not be right.
Literally five replies ago in this very same comment chain, I stated that it was indeed completely legal for employers to behave in this fashion, and should continue to be so; I merely pointed out that it was not right.
"This lawsuit is about harassment, not free speech, and celebrating (legal) "harassment" on the grounds of "free speech" is again, flawed reasoning."
But this comment chain very definitely is about employers firing people for exercising their free speech, on their own time, not related to their employer. I don't think they should do that. What do you think?
The employer controls the company. If keeping someone on board who has opposing views will lead to a worse company and more suffering, it would make moral sense to fire them.
You need to consider the long-term consequences of being comfortable with such behavior on the part of employers. If it's considered admirable to fire people with political views the employer does not approve of, as it is now, that simply makes the country's political divisions ever more extreme. If you work for Google you have to be a Democrat, if you work for McDonnell Douglas you have to be a Republican. Soon enough you won't be able to live in certain places if you have certain political opinions, because you won't be able to find anything more than menial employment. At best, we have two angry and completely distinct political sides, with absolutely no understanding of the other or willingness to compromise, staring at each other over state borders and fighting dirty for every nationwide policy. At worst... well, there's no limit to the "worst" part.
Now, consider the alternative philosophy: employers explicitly do not care about their employees' behavior on their private time as long as it doesn't involve the employer. Not only do we avoid political segregation, but under this scenario, you can hold whatever opinions you want, and you can get into endless meaningless flamewars with the other side on social media without worrying about retribution. I really have trouble understanding why anyone wouldn't prefer this to constantly having to look over your shoulder, wondering what your employer might think of your opinions.