If it is greyed out, it is disabled. Looks like in this example, the Vendetta rule above it is being used instead of the disabled one.
If you want to edit the default rotation, press the “COPY” button at the top-middle of the page to make your own copy of it. Then you can edit your own copy. Reload the simulation page if it is open, and your new rotation will show up in the list of options when simulating.