Lucy Kemnitzer writes in the comment section:

Our own experiences after the Loma Prieta quake is that outsiders are very much into destroying damaged buildings. FEMA had a program where they'd bulldoze your house for free for a limited time. Getting buildings properly assessed would take much longer, and a lot of buildings were bulldozed that shouldn't have been, including our beuatiful sandstone and brick nineteenth-century courthouse, which was supposed to be about to fall down of its own accord but resisted the wrecking ball for several tries. In this case, the feds are going to be even pushier about it, and it will take outright rebellion to keep serviceable old houses.

As for mold -- mold is killable and cleanable. It's a health hazard while it's growing and sporulating, but it's not a structural threat to the houses. The houses will need super cleaning anyway: that water that they've been under is dirty.