He complains in a very infantile way about "Business types" who only cares about selling an idea, but ultimately he's leaving Medium because it's a bad marketing decision for him. He says he doesn't want to be associated with medium because it conveys an image of bad content that he does not think it's good for his artwork. He's leaving Medium because of his personal brand.

There's nothing on Medium itself that inhibit the display of the art he wants to share. Medium as an platform, it's enough for his needs. But it is the brand and the marketing aspect of it that he does not like. He is not that different from those "business types". He doesn't see just a platform for sharing content, he sees a brand, and this brand is bringing a negative value to his own brand as an artist.

Besides, this world view of "business types" and "artists" is simplistic and childish, is a persuasive argument to convince us of the legitimacy of his artwork. It is Another marketing strategy: I am the real artist, my artwork is of original legitimacy, different from this capitalist world we live in.

He is obnoxious, loud, and his reasons are contradictory.

Even though he has a point: There's too much self-help on Medium.