Removing VPN apps from the Appstore does not compromise the privacy of any Apple users, and does not prevent existing users of these apps from continuing to use them on their devices. I would imagine Cook fought pretty hard to protect the privacy of Apple users to get this concession from the Chinese censors. For comparison, on Android, China is forcing users in Muslim regions to install apps that scan for "terrorist content" and track user activity.
https://thinkprogress.org/china-muslim-surveillance-policy-c...