It isn't a legal issue now so much as a social issue. Even if there were strong employment protection laws enforcibility would make it difficult to prove.
Such stupidity is unfortunately sustainable even though it is far from wise. Unfortunately good management and sense is often fragile despite being ideal.
We have the same freedom of speech that we've always had.
> Are we that sensitive, scared, and close-minded?
The online community seems to be. Good thing it's just a very vocal minority.
> Is this sustainable?
Online: yes. IRL: it wouldn't be, but that's why it doesn't spill out into real life that often, and when it does, it's discouraged.
Are you being sarcastic? The "very vocal minority" has seemingly limitless power to ruin people's lives over words they don't like. Businesses are forced to close, professors are forced to resign. We're passed the point of being able to say "it's just the internet," and it's time we all acknowledged that.
But the same culture of freedom of speech that "we've always had?" Decidedly not. And without that culture, the First Amendment will wither and become eviscerated over time.