Re-Raising the River with the Bottom Full

Why do people do this? Perfect example from this heads-up game I just played on stars. I suck out on the river, pretty much putting him on a 5 when he smoothcalled my turnbet. I pretty much have the nuts on the river so I’m thinking: “Well, we’re probably splitting this one, but why not shove?”. Guess I was right.

Betting weak hands on the river is “the worst play in poker”, but re-re-raising on the river with the bottom full must be second in line.

PokerStars Game #21234303256: Tournament #114482161, $11.00+$0.50 Hold’em No Limit – Match Round I, Level I (10/20) – 2008/10/16 2:59:46 ET
Table ‘114482161 1′ 2-max Seat #2 is the button
Seat 1: Teh Jinx (1580 in chips)
Seat 2: acarmisino (1420 in chips)
acarmisino: posts small blind 10
Teh Jinx: posts big blind 20
*** HOLE CARDS ***
Dealt to Teh Jinx
acarmisino: calls 10
Teh Jinx: checks
*** FLOP ***
Teh Jinx: bets 20
acarmisino: calls 20
*** TURN ***
Teh Jinx: bets 60
acarmisino: calls 60
*** RIVER ***
Teh Jinx: bets 120
acarmisino: raises 120 to 240
Teh Jinx: raises 1240 to 1480 and is all-in
acarmisino: calls 1080 and is all-in
Uncalled bet (160) returned to Teh Jinx
*** SHOW DOWN ***
Teh Jinx: shows (a full house, Jacks full of Fives)
acarmisino: shows (a full house, Fives full of Jacks)
Teh Jinx collected 2840 from pot
*** SUMMARY ***
Total pot 2840 | Rake 0
Board
Seat 1: Teh Jinx (big blind) showed and won (2840) with a full house, Jacks full of Fives
Seat 2: acarmisino (button) (small blind) showed and lost with a full house, Fives full of Jacks