I grabbed 80+ domains using js console from a Finnish media holding company website (their results rank high, but all are paywalled -> useless). My intention was to block all of their newspapers. The links there had www. prefix, so I had comma separated list with www. beginnings which I copied to the Kagi bulk add. Because of the prefix, the bulk block did not work. My mistake, but I'd appreciate if on the bulk add page there was a note that the subdomain matters or that I should not have the "https" protocol prefix included with the domain list.
I can click the trash icon manually pretty quickly so manual deletion is not a problem, except after the click I have to wait for the delete request to happen. Could the UI remove the item before the deletion has completed and if the deletion fails just re-show the item with error? That could make the page feel snappier and allow users to (quite) rapidly and repeatedly hit the trash icon to remove all.
In the end I managed to achieve my goal of having them blocked