Why is the word 'appetite' appropriate in this context?

In his book about Bill Clinton, Christopher Hitchens describes how, in a 1992 speech on an event hosted by Jesse Jackson, Clinton "ambushed" Jackson by picking a fight with certain anti-White rap lyrics. Hitchens relates how, in reaction to this, Jackson "exasperatedly described the hungry young candidate as 'just an appetite'"

Why does Jackson use 'appetite' here? Is this an idiom I'm not familiar with?

I do see the potential wordplay on 'hungry' but I wonder if that's really supposed to be the punchline here. Since if it was, it seemed a bit off-target for Jackson quite clearly intended to rebuke the presidential candidate's behaviour, which is something else entirely than scoffing his hunger for office.

It's poorly expressed. Hitchens sometimes had editing that was slighlty sloppy.

Here it is expressed more clearly:

Jesse Jackson said in 1992: ''I can maybe work with him but I know now who he is, what he is. There is nothing this man won't do. He is immune to shame. Move past all the nice posturing and get really down in there in him, you find absolutely nothing . . . nothing but an appetite."

Senator Bob Kerrey, the Nebraska Democrat, was a bit gentler: ''Clinton's an unusually good liar, unusually good.''

Both quotes come from William J. Bennett's solidly valuable new book, ''The Death of Outrage -- Bill Clinton and the Assault on American Ideals'' (The Free Press). Read it, particularly if you are sure you won't agree.

In other words, it's an image: "He's nothing but an appetite." In other words, he wants to gobble everything up for himself, is my reading.

New York Times