to me. The only proof he showed is he "checked their streaming stats" (but how exactly to prove that? more details pls).
Last has a fixed time (7pm) when he starts his stream, and a few minutes of a waiting screen before he actually appears. We can easily see about 50-100 viewers already tuning in. Is it that hard to imagine a guy who attracts 5-10k concurrent viewers every day has 100 of his fans tuning in at a time he tells them that he will start the stream?
Same for the other big streamers.
But what's more hilarious is accusing the 50-100 viewer streamers of viewbotting. Like it's not even worth the effort for them to do so.