Reversed intelligence does not look like natural stupidity. If Alice consistently disagrees with you, then she must (1) be as smart as you and (2) want to taunt you. Point (1) is unnecessary if she has prior access to your opinions (does she?), but point (2) is very weird. (Taunting LW generally is much more plausible than taunting you personally.) Another causal link that avoids (2) is that she might annoy you so much that you change your opinion to oppose her. I very much doubt that these people accurately negate your personal opinions, but if they do, this seems to me the most likely scenario. (maybe this is #3?)

Natural disagreement, whether due to your error or Alice's, should look like she regresses from you to some reference population, such as LW's, the general population's, or an ideology. Thus David Gerard's question seems to be key.

Your three hypotheses about attention seem likely to me:

• What I am actually detecting is smart people who have strong opinions on, and are likely to comment on, areas where I am either wrong, or have a minority opinon.
• These people comment only on difficult, controversial issues which are selected as issues where people perform worse than random.
• Many of these comments are in response to comments or posts I made, which I made only because I thought they were interesting because I already disagreed with smart people about the answers.