Q:

Why can't I read comments on a locked answer?

I saw this note on an answer today:

This post has been locked due to the high amount of off-topic comments generated. For extended discussions, please use chat.

I totally understand locking preventing edits and new comments etc, but why can't I even read (out of morbid curiosity at least) the comments that made it before the lock?

A:

As Oded noted in comments, it's rather common for moderators to clean up the comments that led to locking a post prior to applying the lock. This is usually because they noticed a bunch of comment flags in the moderation dashboard (where they probably deleted the worst of them) and then visited the post to see what else was needed.
It's sometimes easy to overlook a comment or two after cleaning things up that now seems out of place once the offending comments were removed; if you notice this just flag those comments as no longer needed and they'll get cleaned up.
The reason for locking is shown more specifically to let folks know what we're hoping to avoid once the post is unlocked, even though it does a great job of telling folks why we locked it :) We'd rather tell folks to slow down and be careful rather than leave a bunch of sensational wreckage at the side of the road, so to say. 

