There are some topics where an issue is a learning opportunity and a discussion can be had. Technical disagreements are a classic case. There are others that are so played out and hurtful that it's not worth it.
I don't need to spend an hour giving a coworker an explanation of why their actions are hurtful. They just need to know that they are. If they're interested in getting better, they can go to their nearest search engine and read some history. If they're not, they can just know to keep their mouth shut next time.