The first reason; His past as a prime minister should not even be mentioned, if he did wrong he should pay the price this is elite cronyism pure and simple.
Second reason; Potential threats from inmates; I am sure if they wanted to they prison officials could make sure he was safely looked after again a feeble excuse.
Third reason; his health needing constant supervision; Everyone with half a brain knows this was BS, look how quickly he recovered & has been able to travel around upon his release.
Thaksin should man up and admit he was trying to con the people - Really sad and it does further illustrate the kind of person he really is.