Actually, the only coded exclusion is self. (You cannot sponsor yourself). There is a pointlessness to sponsoring some accounts (they never post or comment, so why? just why?) but they can still be sponsored. Blacklisted account can continue to grow their unit levels, they just don't get upvotes.
We are working on a system that will redistribute the accrued balances from these scenarios (blacklisted and inactive) to the rest of the member base.
You are welcome to edit your submission and I will review again (or you can resubmit if your edit is substantial.)