Google's updated their search engine scripts or codes, i believe. As seen through July 2023, the ublacklist dialog has gone missing under the url where it has been always. What was blocked still appears in results despite. Browser wasn't updated, so that's not the cause. There is no way to block them at the moment. Please fix this soon.
Updated: As of early March 2026, I've seen a different change. You can block them in Google's search results but not immediately. There seem a bug where each time you want to block any site, it won't be active until you click the extension button to activate it. It isn't as automatically active like before. Each time the page is reloaded/refreshed, the extension will require to be clicked first in order for the sites to not show up again. I believe this has something to do with "Only when clicked" shown when the extension icon is right clicked. It is the only already auto selected option placed and there are no alternatives. Why is that even shown then?
This has become an annoyance yet again.