One possibility is that there are a very large number of things they could measure, most of which have low information value. If they chose randomly we might expect to see an effect like this, and never notice all the low information possibilities they chose not to measure.

I'm not suggesting that they actually do choose randomly, but it might be they chose, say, the easiest to measure, and that these are neither systematically good or bad, so it looks similar to random in terms of the useful information.