A custom off-topic reason generates an auto-comment with the reason for the close vote.
Specific off-topic close reasons are no longer displayed in the post itself, unless you are the poster or you have 3,000 reputation.
Regular users (i.e. not the poster and not those who have 3,000 reputation) cannot see why a question was deemed to be off-topic unless it was closed with a custom off-topic reason.
This seems to be inconsistent. If we don't want them to know the specific reason why a question is considered off-topic, then they shouldn't be able to see it when there is a custom off-topic reason. If we do want them (or at least don't care if they are able) to see the specific reason why a question is considered off-topic, then they should be able to see it even if it was not a custom off-topic reason.
The system should generate an auto-comment for all off-topic reasons just like it does for custom off-topic reasons. This way anyone will be able to determine the specific off-topic reason by reading the comment, whether a custom reason was used or whether one of the existing specific reasons was used.
I am aware that the suggestion of auto-comments was made on at least two previous occasions (here and here). However, both of those suggestions were made at a time when the post itself displayed the specific off-topic reason to all viewers. This is no longer the case, and therefore auto-comments would serve a much greater purpose. Additionally, the discussion in the previous requests was primarily related to the time period before a question gets closed (i.e. during the voting process). Here I am primarily concerned with what happens after a question is successfully closed.
A concern mentioned in the previous discussions was that the identity of close-voters would be revealed via an auto-comment. Aside from the various possible ways to implement this without revealing anyone's identity, a custom off-topic vote and a duplicate vote already generate auto-comments that reveal the voter's identity. If it's not a problem in those cases, why should be a problem in the case of specific off-topic reasons?
In light of the above, can this idea be reconsidered?
This request is very different from this question. That is about no longer being able to see which close reason you yourself selected. This is about an auto-comment that would be generated on the question.