The purpose of making politics into art is to harness the power of art for your politics. If you forget the art then you've lost that purpose.
I think you're misusing the sense of "lost purpose". A 'lost purpose' describes when you lose the actual purpose (in this case 'politics') and replace it with a mere tool that was supposed to work for that purpose (in this case, the art).
In this case the problem is the other way around -- not admiring the sword for its beauty and forgetting to cut, but rather forgetting that the sword needs to be sharp in order to cut..
You're trying to harness the power of art for your politics. If you forget politics, you've lost your purpose. If you forget art, you've lost your purpose.
Today's post, Politics and Awful Art was originally published on 20 December 2007. A summary (taken from the LW wiki):
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This post is part of the Rerunning the Sequences series, where we'll be going through Eliezer Yudkowsky's old posts in order so that people who are interested can (re-)read and discuss them. The previous post was The Litany Against Gurus, and you can use the sequence_reruns tag or rss feed to follow the rest of the series.
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