This is so that we can add and remove css/html from your original layout and do the experiments with new layouts on desktop/mobile/tablet. None of your original content will change - no links change, none of the original content is altered and remains fully index-able as normal.  

If you think about the Ezoic system as changing the 'wrappings' of the content so that it can show new layouts styles (by changing fonts, colours, ad styles, menu appearances, sizes, backgrounds and a bunch of other things), then you can see why we need to put that clause in the terms.