I'd think of it more as pointing out a pervasive bias and suggesting some ways to attack it (i.e. discuss issues at the object level if possible; avoid rhetoric; don't gratuitously insult the opposition) than forbidding discussion altogether. It's almost a cliche by now to point out that Eliezer's politics sequence makes much narrower recommendations than have been attributed to it.
That said, we probably should avoid issues that we've historically been unable to discuss without shedding more heat than light.
But why cannot it be done e.g. by a largely pro-capitalism fellow writing a charitable steelman overview of anti-capitalist sentiments? How would it not have the effect of un-mindkilling? I actually intend to try it and I would try it here in LW Discussion if not for the fear that it will be downvoted be the strictly anti-politics members.
One of my favourite Less Wrong articles is Politics is the mindkiller. Part of the reason that political discussion so bad is the poor incentives - if you have little chance to change the outcome, then there is little reason to strive for truth or accuracy - but a large part of the reason is our pre-political attitudes and dispositions. I don't mean to suggest that there is a neat divide; clearly, there is a reflexive relation between the incentives within political discussion and our view of the appropriate purpose and scope of politics. Nevertheless, I think it's a useful distinction to make, and so I applaud the fact that Eliezer doesn't start his essays on the subject by talking about incentives, feedback or rational irrationality - instead he starts with the fact that our approach to politics is instinctively tribal.
This brings me to Joseph Bottum's excellent recent article in The American, The Post-Protestant Ethic and Spirit of America. This charts what he sees as the tribal changes within America that have shaped current attitudes to politics. I think it's best seen in conjunction with Arnold Kling's excellent The Three Languages of Politics; while Kling talks about the political language and rhetoric of modern American political groupings, Bottum's essay is more about the social changes that have led to these kinds of language and rhetoric.
Video of a related lecture can also be found here.