I mean random as in the two colours are selected at random.
I think it's not really relevant to select colours in a void. Colours are good for a purpose. This is especially relevant on websites. I love yellow but I would hate it when it's used for text on a white background. Stuff like that.
I certainly agree that context is important when picking a color. I don't think the conclusion is that whatever color is selected the most should be used for everything because it's the most popular. But when presented with two colors the way the site does, there is generally one I prefer over the other. Whether this preference information is actually useful is a whole other question.
I think it's not really relevant to select colours in a void. Colours are good for a purpose. This is especially relevant on websites. I love yellow but I would hate it when it's used for text on a white background. Stuff like that.