Yes, as a taxpayer, I would like an answer to that question. I have to pay for homeowners insurance on my house. Why are you telling me that I should pay off someone else's mortgage when their homeowners insurance should do that?
Homeowners insurance does not pay for flood damage from rising waters. A lot of the homes destroyed were in areas that were not considered flood zones so they were told by insurers and mortgage companies that flood insurance was not required. Therefore they had no insurance that would cover their loss. Could they have bought flood insurance anyway? Sure, but that's a different argument.
This is not a "gift". It is a loan which would be repaid as properties are redeveloped.