Everybody seemed to be going backward from assuming AK's guilt at 50-50, whereas komponisto went forward from the background probability.

I think I can see why. komponisto pretended to be a juror following the "innocent unless proven otherwise" mantra and updating on the evidence presented in the court. We, on the other hand, did what komponisto challenged us to do: figure out the answer to his riddle using the two websites he gave us. This being a riddle, not a court, we had no reason to favour one hypothesis over the other, hence the 50-50.

That being said, I did favour one hypothesis over the other (my stated priors were 75/75/25) because at the moment I paused to write down an approximation of my current beliefs, I had already updated on the evidence presented by komponisto himself in his post, namely, that there was a trial against AK and RS.

Maybe the reason why many of us gave so much importance to the fact that those particular individuals were on trial for murder was because it was our very first piece of information; and I don't think it's right for rationalists to do that.