"Safari detected that an app or service interfered with clicking" ("Safari ha detectado que una app o servicio ha interferido con el clic")
Recently I had a problem with macOS Catalina 10.15.6 that Safari did prevent enable extensions. After many retries, and browsing the Internet forums, I decided to try another way. And I finally found the solution:
With a text editor, for example, nano, edit the file Extensions.plist (ensure Safari is closed):
$ nano ~/Library/Containers/com.apple.Safari/Data/Library/Safari/AppExtensions/Extensions.plist
And append the text for each extension you want to enable:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>com.agilebits.onepassword7.1PasswordSafariAppExtension (2BUA8C4S2C)</key>
<dict>
...
<key>Enabled</key> <--------- THE MAGIC (REMOVE THIS COMMENT)
<true/>
...
</dict>
</dict>
</plist>
I signed up for a Github account to thank you for this! After several months of dealing with ads and saying I'd get around to the downgrade Safari/install extensions/update Safari workaround, I was able to enable Ghostery Lite in five minutes by adding keys to the Extensions and ContentBlockers plists.