When first creating a new Site Page or News Item, the button to switch Comments on/off does not appear, even when editing between saves. If you want to disable comments on a new Site Page, you have to publish the Page first and then Edit it again for the Comments section and button to appear.
Would it be possible for the Comments On/Off button to appear as soon as you create a new Site Page?
To me this is "by design" and it would require to change the way page comments are displayed...but as you say, you need to publish first the page in order to see the comments area and be able to disable it
I agree this should be present at the initial creation of content, not post-publish. I'd also like to be able to turn it on/off for more than one page at a time (and, in some cases, for an entire site to default to no comments at creation), but these are probably off-topic here?