I suppose I could start a new Skype account. Did Skype upload them to its server, so that when I install a new copy of the app and log in, they just get downloaded again? Or does it have a secret file that App Zapper does not delete. This time I'm sure I didn't authorize the import. To my amazement and horror, it listed all my contacts from my address book.
So I used App Zapper to delete Skype and all related files, then reinstalled. I suspect Microsoft has made it difficult to delete them, for its own nefarious purposes. Maybe a recent Skype update makes it harder. I found some answers, but they don't seem to work. When I try, I get an alert that says, "To delete this contact, remove them from your Mac Contacts." I Googled for the answer.
It's none of Skype's (Microsoft's) business and I don't trust them to respect my privacy. I probably pushed the wrong button during setup because it imported my entire Mac address book as Skype contacts.