The concept of Chatsubo, a neutral forum for roleplayers to get together in EVE and discuss rp topics, collaborate, and discuss current events was a good one, and one reason that Backstage remains a useful environment. However, the discussion of current events, and the realization that the bitching session forum could be used to vent personal grievances about other players 'doing it wrong' made the environment more popular as an OOC battleground/propaganda zone rather than the constructive/cooperative elements it was designed for. Removal of the bitching forum didn't stop this behavior, which eventually spilled over into all other areas of the forum resulting in many individuals giving up on the forum altogether. Although some attempt was made at rebuilding after the calamity with greater moderation enforcement, the damage had already been done. Those seeking collaborative contribution had vowed never to return, and now the culprits in the Great Chatsubo Forum Wars were also not welcome either, resulting in no one wanting to use the forums at all.
So no, blocking people isn't the problem so long as there are still individuals who want to contribute, collaborate, and discuss.