It sounds like there's two main options:
1) FEMA wanted to have a real press conference to answer the questions reporters had been phoning in all day, but because of their own incompetence, they were unable to organise it well enough to ensure that real reporters could actually attend, so with two minutes before the cameras went live, they quickly shoved staffers in the seats and said "quick, do your best reporter impersonation so we don't look like fools!" and figured there was no harm no foul because the staffers could just ask the questions they'd been getting on the phone all day from real reporters anyway.
2) FEMA was not trying to have a real press conference at all, but rather was trying to hoodwink everybody with a fake press conference that would look like a real one but be ensured to make sure FEMA came off looking good, and they did this because of how bad they ended up looking in the last natural disaster. And yet, because they were incompetent, they didn't pull this off well at all, and so real reporters were able to figure it out and pull back the curtain.
In the first option FEMA is just incompetent. In the second option, they are deceitful and scheming as well as incompetent. Either way it's not too good for them, but right now I actually believe the first option is more likely.
I don't think anyone understands how inept and shameful this act is. Staging a conference to talk about your efforts to handle a crisis. You totally loose the public trust.
