Does it result in anyone deeply learning the lessons of history behind it all? Or do they just learn to keep their mouth shut?
If someone is expressing bad ideas, then you can use their comments a an opportunity to teach a deeper lesson. If they just shut up, the conversation never happens and no learning takes place.
I suspect that a lot of well-meaning people do not really understand much about racism. How could they? It's such a dangerous topic that you can't even ask basic questions without putting yourself at risk.
Maybe that's fine in the sense that fewer people are offended. But I am not convinced that such a shallow lesson will last more than a couple generations, and the "shut up" lesson creates a lot of collateral damage to the overall culture.