Because all three of those are, at the core, the very same thing? Whether removing, adding, or modifying, you're changing the contents of the HTML/CSS. Whether

Because all three of those are, at the core, the very same thing? Whether removing, adding, or modifying, you're changing the contents of the HTML/CSS. Whether it should be done in a more finely grained way, not sure, but if you have the permissions to modify then by definition you have the permission to remove or add content.