how do I delete an app from the organizer left menu

1. Delete the apps from Xcode Organiser by going to ~/Library/Developer/Xcode/Products and deleting the folders from there.

2. Close and reopen the Organiser.

You can go to Xcode > Window > Organizer, right click on an archive and click open in finder, then press Command + DPadUp to move up a folder and see all the archives. I had 120GB.

You need to remove the App's archive's from ~/Library/Developer/Xcode/Archives along with ~/Library/Developer/Xcode/Products to remove it from Xcode's Organizer completely.