Nothing. Most of the board members probably agree with the sign. What they are doing is enforcing the rules according to Florida law. It's too bad people won't learn how things work before they start calling names.
It's still wrong, don't matter what end of the stick it's on . These guys are fighting and dying for us. If there should be an exemption, it should be for these. It's not like it's big and ugly, but I guess it could be offensive to socialists.
There's right and wrong, legal and illegal. Occasionally they coincide.
Decent folks would be able to figure out a simple way out of this. Ignore the damn law. And the decent judges would not let such cases quibbling about them ignoring the law into their courts until the legislature got its thumb out its butt and fixed the darn law.