The functionality for approving subscriptions is available via the approve button in the subscription list and via the details button (opens <site_access_name>/newsletter/subscription_view which has provides the Approve-button.)

IMHO, editing the user is a task separated from approving.
It should be possible to alter user info without approving.

Steps to reproduce

1. Subscribe to a newsletter configured to not automatically approve the subscription
2. Edit the newsletter user and store changes
3. Now the subscription is automatically approved