Having an Unsubscribe All Lists checkbox doesn't minimize that. It just adds form noise and pointless work for a dev. The minimization already happens with the preceding checkboxes to select each list to unsubscribe from, but that's just as inherent to the form as the desirable feature of being able to keep certain subscriptions while unsubscribing from others in an efficient way.

A button or link in place of the 'All' checkbox makes sense and is easiest for users to understand, and has less user actions required.

Treat your customers well even when they're exiting (especially) so they remember something good next time they consider you. "Well at least they made it easy to unsubscribe" is better than "Well they made it unnecessarily complicated to unsubscribe". No need to add insult to injury.