There’s a reason that article notes that they “could not independently verify the ministry figures.” They aren’t independent or apolitical. The Ministry of Health aren’t frontline doctors and nurses, they are the Hamas-controlled bureaucracy that oversees them. Hamas long ago purged anyone from the ministry that wasn’t specifically loyal to them.
Why do you think Hamas would work so hard to purge the Palestinians in the Ministry who were neutral or Fatah-aligned? Is there a compelling reason to think an institution designed to serve a party or faction to the exclusion of everyone else would (or could) serve anyone else?