As per this question, routined is an Apple daemon that introduces some problems in High Sierra onwards: routined wants to use the "Local Items" keychain alert
Experiments with killall over the course of months show that this service is needed for ... nothing that we actually run. The only web hit on usafge suggests its needed for Apple doing background tracking on your laptop's location, which is hardly attractive :). I'm very happy to get rid of it once and for all. If only I could get launchctl to do its job...
Apple doesn't allow "Cancel this and ALL attempts by this service". Apple engineers coded the service to spam the user many times a second with a modal dialog action (ugh).
Unfortunately, the standard approach to stopping this rogue process doesn't work. As described here (How do you prevent a process from automatically restarting? (specifically, sophos antivirus)) launchctl should be able to manage it, but cannot: it claims the service doesn't exist (although the plist file is right there in /System/Library/LaunchAgents/).