Hello IP user!
It is true that we typically want to see reliable, external sources for all data which is hosted at Wikidata. However, for various reasons this is not an easy task, and we are working hard for a satisfying solution at some point in the future. This also includes accepting unsourced data at Wikidata, as long as it is reasonable to assume it is correct. This applies to my opinion for the country of citizenship of John Deely (Q12365424), thus I re-added it after it got lost during the revert.
The situation is a little different with the death date of this person, which is said to be just two days ago. We have ongoing trouble with death notes of still living persons in the Wikimedia universe, and typically prefer to wait until there is a reliable external source which verifies the death of the person in question. It does not cause any trouble if the death note does not appear immediately at Wikipedia (or Wikidata); it potentially does, however, harm a lot if the person actually has not died, and external media or search engines such as Google are picking this information up (they do, even right now).
Since I was not able to find an external source for Deely’s death, I removed the claim. It typically takes some days until a reliable source shows up.
Best regards!