Parole Board manager Alistair Spierling sympathised with the Smith and Croskery families, both of whom he knew well. But he said the law required the board to notify victims' families about hearings. "Some victims choose not to make submissions."
By law, a prisoner must be considered for parole after one third of the sentence is served. A decision to release is based on the risk to the community and Spierling said paroled prisoners had a clear incentive to stay out of trouble.
"The parole hearing has to be about the offender and whether they should be released."
It is 10 years since Choy, 40, was robbed and beaten to death outside a South Auckland house. Seven youngsters were given prison sentences for murder, manslaughter or aggravated robbery - including Bailey Junior Kurariki, who became New Zealand's youngest convicted killer at the age of just 12.
After the horrific killing, Michael's stepfather Ken Croskery became an active campaigner in the Sensible Sentencing Trust. He attended every court appearance and parole hearing of every offender - as many as six a year. The 73-year-old was preparing for two major hearings next month - for lead offenders Alexander Peihopa, now 25, and Whatarangi Rawiri, now 27 - when he collapsed and died on December 29.
Rita Croskery, Choy's mother, said her husband was fit, healthy and looking forward to travelling to Monaco for the Grand Prix in May.
"It's so sudden, it's such a shock," she said. The stress of Parole Board hearings had caught up with Croskery over the past few months, she said. "You're going through it all the time, it's always traumatic."
The couple refused to forgive the youths involved in the attack and were opposed to their release from prison.
"After Michael died we were determined to do something to try to fight the crime," Rita said. "We've being trying to do something about it for so long. In the end you can only do so much."
Sensible Sentencing Trust spokesman Garth McVicar said he found out about Croskery's death at Bevan Smith's funeral.
"They kill one person - but they always kill more than one person," McVicar said. "You can't have a life because of all the hearings. The stress is enormous.
"If they served a true life sentence, the Smiths and the Croskerys could have come to terms with what happened.
"A lot of people feel like the system is there to torment them."
Bevan Smith, a close friend of Ken Croskery, died on Christmas Day after a stroke.
Smith, 60, was the father of Kylie Smith, brutalised and slain by Paul Bailey, who was on parole for the attempted rape of another girl.
Smith's wife Dawn believed the stress of Parole Board hearings had also played a role in his death.
"It was very daunting. You had to speak in a certain order and you could only speak once and, of course, no one really knew what a parole hearing was all about," she said.
Despite the stress, she said not turning up to the hearings would never be an option
"Since Kylie's death, Bevan changed," she said. "His health changed, his personality changed. It broke his heart. I don't think time heals. I don't think it ever heals."