This has nothing to do with freedom of speech, and everything to do with workers' rights. You can't be fired for belonging to a protected class, but you can be fired for literally anything else - hence people are still rarely punished for firing members of a protected class.

There was an upheld case a few years ago where a man fired one of his employees for being too sexy. Not acting too sexy, or dressing too sexy, but being too sexy. You can fire someone for wearing Adidas, or for breathing too loudly (unless it can be shown to be the effect of a disability.)

The idea that we should have special rules for racists and sexists is an insult. It would be in effect creating a protected class for bigots, who could still be fired for wearing green on Thursday.

The most absurd part of this is that the vast majority of the people decrying "cancel culture" are the most antagonistic to any normalization of worker's rights, or enforcement of minority protections. Apparently, the only real racism is when you call someone a racist.