It IS pure hunger made manifest. One of its main purposes is to destroy matter, so looking at corporeal beings, it might call it "hunger".
Or simply: "My power reserves are low i need to disintegrate stuff."
About the gate joke: A sphere of annihilation is conterminous to all planes adjacent to a given plane, as it is a hole in the fabric of the multiverse.
It cant see the gate because its existing on both planes. It sees everything on both sides so it doesn't notice a "hole" between the two.
The "Who hits lightest" scene might be explained with it having the ability to use telekinesis. With space-time manipulating abilities its just a step away.