I was just now led to this question, which appeared under "Hot Network Questions". However, it is locked since yesterday. Certainly, questions which are closed or locked should not be advertised as hot questions, so I believe this is a bug.
As far as I know and remember, closed questions are already excluded from the Hot Network Questions list, or more accurate a closed question can't become "Hot".
So, if a question is off topic for a site and should not get new answers, a moderator or five ordinary users can just close it.
Such locks as the one on the question you linked to are quite common and meant to prevent comments, not answers. This should not affect the question visibility or its quality.