It certainly is.
Answering your question : maybe because the post is from version 0.89 which is about 3 years old? Or maybe because if you go to the profile of the aforementioned, his wall is full of users saying RIP? I don't know about you but if I'm interested in someone's post and I see that information is missing, it's outdated or I'm just interested in seeing more of their content, I go to their profile to see if there's news. Although I totally agree with you, that guide should not be there, it just confuses new people, I don't know if they left it there out of some kind of respect in his memory or if the moderators just don't care about this thread, who knows.