There's been many captains over the years who've retained a place in the first team despite being in poor form themselves. The best recent example of this would be Ricky Ponting who is playing on past glories. If Ponting wasn't the Australian captain he may well have been rested or even dropped by now.
Then there are those captains who aren't proven performers in certain formats but they get picked to play in those formats because their cricket board wants one captain for all formats. From a Pakistani perspective having Malik as Test captain and Younis as ODI captain meant that more deserving batsmen were kept out of the Test and ODI sides respectively.
Sammy however is in a 3rd category. He supported the WICB during their dispute with the senior West Indies players. He led the West Indies B team and so the WICB are keeping him on as captain. Perhaps they dont feel they can trust anyone else, perhaps they're rewarding his loyalty or perhaps they think he does make a good captain.
Whatever their reasons for keeping him as the captain, he doesn't deserve a place in the West Indies first XI. Sammy has a batting average of 20 and a bowling average of 40 over 53 ODIs. He's just not an international standard player yet he's in the team because he's the captain.
Am I alone in thinking that's he holding back the Windies ODI side both physically (they are playing with one less international class player) and mentally (they know he's in the side as the WICB's representative)