I searched for:
All the results still show "More results from this site" on the three dot menu.
It would make sense to detect the site filter and not show that option, because it starts a silly query like site:kagi.com site:kagi.com
Additionally:
The opposite (remove results from this site) should actually strip the site:kagi.com tag and replace it with -site:kagi.com. Right now it keeps the site and adds -site, so it obviously returns no results.
