The setting is "Add OP tag".
When it's off, this post, for example, shows comments. Turn it on, and the comments disappear. There are other posts where the comments still appear even when the setting is on, such as here.
The difference appears to be whether the OP posts a comment. When they do, all comments seem to disappear with the setting on.
If you're not seeing the behaviour, it's possible I've got other scripts or modifications running which might be interfering with yours, not sure!
Kbin: delete articles in other languages