This is a hilariously optimistic, naive, disconnected from reality take. What sort of "proof" would be sufficient for you? TFA includes of course data from the authors own server logs^, but it also references real SDKs and business selling this exact product. You can view the pricing page yourself, right next to stats on how many IPs are available for you to exploit. What else do you need to see?

^ edit: my mistake, the server logs I mentioned were from the authors prior blog post on this topic, linked to at the top of TFA: https://jan.wildeboer.net/2025/02/Blocking-Stealthy-Botnets/