See comment thread on the core mailinglist for our reasoning behind this: https://groups.google.com/forum/#!topic/silverstripe-dev/1nYJU4OxOJ4
This is by no means a measure to lock out your contribution, we are just refining and enforcing our comment policy a bit. It states that the comments on api.silverstripe.org and doc.silverstripe.org are for "hints and suggestions", not for "questions". Through moderation, we can ensure comments meet this standard, and hopefully provide a better value for the community.
If you are interested in becoming a moderator, please contact me directly.