Perhaps my earlier claim was too strong.

Nevertheless, I do think that people on LW who haven't thought about the issues a lot might well not have a solid enough opinion to be either agreeing or disagreeing with the LW one-boxing view or the two-boxing philosopher's view. I suspect some of these people just note that one-boxing is the best algorithm and think that this means that they're agreeing with LW when in fact this leaves them neutral on the issue until they make their claim more precise.

I also think one of the reasons for the lack of two-boxers on LW is that LW often presents two-boxing arguments in a slogan form which fails to do justice to these arguments (see my comments here and here). Which isn't to say that the two-boxers are right but is to say I think the debate gets skewed unreasonably in one-boxers' favour on LW (not always, but often enough to influence people's opinions).