Literally any thing the government might have authority over or acknowledge as a freedom could have things get absurd. So the argument that it might get absurd doesn't mean the thing is wrong. It just means that, likely any action, there's potential for consequences, and you deal with them.

You don't back down from a good thing just because it might be hard to implement. So then it just comes down to whether you think removing speech that incites violence is a good think or not. If you think it's good in itself but could be abused so maybe not do it? No, you do it and deal with the hard questions that come along every time you make those decisions.