I suspect that NY, NJ, and CA would be high on many thinking people’s lists.
They aren't going to say that "the rest of America should kick out" New York or California. Or Texas, for that matter -- lot of very active users in Austin (or somewhere else in Texas but telling people they lived in Austin).
If you asked most Americans, I suppose they'd choose states that stood out or made themselves conspicuous in some way -- California, Massachusetts, New York, Texas, Florida. "Redditors" (as they call themselves) chose to expel states that didn't stand out, the wallflowers or milquetoasts of the union -- Rhode Island, Delaware, North Dakota, South Dakota, Indiana -- with Florida and Mississippi thrown in.
If the "redditors" really did choose them, that is. It doesn't look like the thread actually "polled" anybody. It just solicited opinions which the writer of this piece claims to have totaled up (whether he actually counted anything or not).