When he himself is a convicted criminal who SHOULD be in prison himself???

Actually it's a good place to put him and each and every person he appointed to office this year.

I thought the concrete walls were deteriorated from the salt water air.

In that foreseeable - and widespread - emergency, you might not be able to keep track of every prisoner, alternate facilities nearby would likely also be damaged or inoperable, and transportation would be all but impossible.

He listens to all the populist gossip, conspiracy theories and stupidity circulating around and thinks he can gain some kind of benefit by making it happen. Opening Alcatraz is a mantra of those who think we don't jail enough criminals and that's why our crime rate is so high, even though it's not really that high. It's to appease another group of dumbass Americans who believe lies.

With his more Nazi loving pals.c
THAT would justify spending a few bucks to fix it up just for them.
He can have his library there also.