Well it is partially done by theme parts.
First if you like to dismiss them both go into theme (Relive) go to temlates and delete/rename the comment template.
This does NOT influence the core comment template as it is a special designed/adapted 'copy'. and overrides.
So when you should have done this and refresh the page, it would seem to be have gone. Ok.
Now step 2
Since you use the About page and the comment template from theme is 'gone' . you might notice then (refresh the About page), you could/would notice there is now a new 'bar' for comment.
Oh no ;-) well that is an option for page... Go into edit mode of the About page (custompages/plugins) > About.
The second bar option (page options) has likely been set to use Comments ON (etc..) disable it and your done.