I think you are misreading his comment. He is saying that on a VPN it is standard behavior that if you visit site A and site B they will both see you connecting from the same IP and can infer you are potentially the same person.
Site A and B have to collude in order to make that inference. Outside of Cloudflare, no one is colluding at that level.
Site A and B have to collude in order to make that inference. Outside of Cloudflare, no one is colluding at that level.