Because he has no good place to post them elsewhere and expect a reasonable discussion. :(
Which suggests there's a market for a web forum whose policy is that controversial topics are welcomed and discussion of those topics must be reasonable no matter how reprehensible one considers the position one is discussing, and the moderators assiduously ban/delete violations of that policy.
As you say, LW is not that forum, and does not wish to be.
Incidentally, I would be astonished if such forums didn't exist already. Were I looking for one, I would probably ask around on someplace like FetLife.
Admittedly, there are some mainstream-controversial topics that get discussed in that way here, with that sort of social norm, and I expect that in some communities the opinion of LW is tainted by those discussions in the same way you discuss. But the consensus opinion of LW seems to be that the opinions of those communities don't really matter very much.
there are some mainstream-controversial topics that get discussed in that way here, with that sort of social norm, and I expect that in some communities the opinion of LW is tainted by those discussions in the same way you discuss
One difference is a different degree of taboo. Another one, I suspect more important, was the timing. The controversial topics didn't start by someone posting a full article out of the blue. They first appeared as comments in other articles, somewhat related to their topics. Only later someone would write an article about it. A...
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.