I can see the idealism behind this question, but imagine just how hard this could backfire in practice. People discovering to what extent algorithmic ranking manipulates them, and feeds the outrage machine.
And that's what glues eyeballs and generates revenue, so changing the algorithm would work against revenue.
I'm saying it's interesting for Elon, as a major shareholder, to argue in favor of this.
People should be able to customize the algorithm (aka make their own algorithm). As long as that is possible and the options are clear, no one cares if it's open source or not.
ill quote will ferrell
"No one knows what it means, but it’s provocative… it’s gets the people going!"