How do I find the view class of a page I don't want the macro selector on?
Enable debug mode (put $config['debug'] = true; into config.php), and then visit the page you don't want macros to appear
Hover over the debug text at the bottom of the page, and the text in brackets is the view class.
(You should now disable debug mode)
Can users choose to disable extra macro areas?
They can choose to hide the selector in all other places, but it doesn't get any more finer grained than that, sorry.
Developers: How do I stop the macro selector appearing in my add-on?
If the editorParams array has a non-empty noMacros key, the macro selector will not be displayed. (See LiamW_PostMacros_ViewPublic_Create).