Simplifying the tax code makes it easier to file.

Simplifying the tax code is about tax prep. The simpler the tax code, the simpler to file. Though what you say about him wanting to lower taxes is possibly true, none of those posts are about that.

Not relevant because you exclude Elon Musk from the "they" who "have interest in keeping tax filing difficult and unapproachable"? Because he is clearly not one of them: "Simplifying the tax code will increase productivity", "Crazy idea: let’s simplify the tax code", "The tax code needs drastic simplification!", etc. And he seems to have quite a bit of influence in the Trump administration.