Author has no concept of what it is like to take submissions to anything. As someone who is a member of an investment fund that gets way less attention than a top-tier VC, I'll tell you what it is like to have open submissions:

Almost everything that comes through that channel is complete garbage. It has negative utility to read through that stuff because it makes you tired enough that you might actually miss something good if you see it anyway, and it predisposes you toward negativity regarding submissions (which is psychologically unhealthy both for your quality of life and your relationships with potential investees.)

Our hit rate from open submissions was 0.25%, that is, it took 400 submissions to get one company in which we would invest. And that company is one that likely would have come to us through a more-closed submissions process.

One of the most valuable things you can have as a business owner (startup or no) is an understanding of context. Know what the situation is like for the people you are dealing with. Know why they do things the way they do. This author has not built that experience/skill. He is only seeing things from his viewpoint as someone who wants money. Guess what, this makes him isomorphic to every other random startup founder in which a VC is not going to invest.

Use common sense: VCs are financially motivated to find good companies to invest in! If they think something will give them an edge, they are going to try it. The fact that they don't take open submissions should tell you something about the dynamics of the system. You should listen and understand what that something is, because that understanding is valuable.