Slowpoke was explaining how he came be his impression that the game will be released later and why he doesn't expect a beta soon; he also compared his reasons for that belief to the reasons some people have sited for believing the beta will come by tomorrow.
There's no claim of absolute knowledge, just a simple statement that he is basing his opinion on information we all have about the game and its development while others are basing the "tomorrow" prediction off a less than a paragraph of information taken from social media sites that's been heavily read into.
He could certainly be wrong, but he has reasons for believing what he does beyond just wanting it really bad.