If someone uses undesirable words perhaps they will be fired or their business boycotted. As usual when violence is used to control others, the behavior appears to get better but the root cause gets worse.

The professor may censor themselves due to laws but they become a more hateful and intolerant person because of the censorship.
If your goal is to solve the root cause of this problem, you should do the opposite. Get the professor to talk openly about their idea perhaps in a public debate.