Probably because he has so much potential.
And because his ODI failures have been greatly exaggerated. He was completely useless when he first came into the team and he's been just as useless in this series, but he had quite a good run for a while after he was moved to #5.
Chappell-Hadlee Trophy 2005/06
13 v New Zealand (#4)
0 v New Zealand (#4)
59 v New Zealand (#4)
VB Series 2005/06
5 v Sri Lanka (#3)
2 v Sri Lanka (#3)
Commonwealth Bank Series 2006/07
0 v England (#3)
1 v England (#3)
99* v New Zealand (#5)
5 v England (#5)
45 v England (#5)
Chappell-Hadlee Trophy 2006/07
22 v New Zealand (#5)
97* v New Zealand (#5)
12 v New Zealand (#5)
World Cup 2006/07
29 v Scotland (#4)
123 v Netherlands (#5)
Australia in India 2007/08
0 v India (#3)
3 v India (#3)
3 v India (#6)
17 v India (#6)
By position
#3 - 11 runs @ 1.83
#4 - 84 runs @ 21.00
#5 - 424 runs @ 84.80
#6 - 20 runs @ 10.00
(#5, excluding the match against Netherlands - 301 runs @ 75.25)
So, what can we gather from all this?
* Despite either opening or batting #3 in domestic cricket, he doesn't seem to have the required technique to do so. He's been given numerous opportunities at this position and failed regularly.
* He relishes the middle order role at #5 with two unbeaten scores in the 90s and a ton (albeit that ton against the Netherlands..) and he fully deserves further opportunities there.
* He's in bad form currently.
While his form may not justify selection for the next game over Haddin, the comments suggesting he has been a failure for Australia in one day cricket in general are way off IMO, as his performances away from the new ball have been exceptional. I'd expect Andrew Symonds, for example, to struggle similarly if he had to bat at #3 regularly. I don't want to see Hodge at #3 for Australia in ODIs ever again and I wouldn't pick him today either but he's not the failure he's made out to be and I'm certainly for him remaining the "next cab off the rank" for a #5/6 role.