Great question.
At the moment, some forum categories are open to search engines and people without accounts whereas others are only accessible to logged-in members, including Repair stories, which is where most of the model-specific repair information is located.
click/tap here for more detail about which categories are open and which are members only
The decision to open some categories up and keep others members-only was the result of this conversation, which might be helpful to read for the full context:
It may be that the time has come to revisit this question, especially regarding the Repair stories category.