Gud's death on Thursday in Long Bay Jail was the ninth Indigenous death in custody in four months.
GetUp First Nations Justice Campaign Director Larissa Baldwin said:
"I am filled with sadness and anger today.
"Sadness for Frank 'Gud' Coleman. For his family. For those that loved him. For the life he should have lived.
"And anger at the justice system that took him away. At the politicians who could have stopped this. At the indifference that caused his death, and the indifference it will be met with.
"Gud is not a statistic. Tane Chatfield is not a statistic. David Dungay Jr is not a statistic. Tanya Day is not a statistic. Nathan Reynolds is not a statistic. Anzac Sullivan is not a statistic.
"Every single one of the nearly 500 Aboriginal and Torres Strait Islander people who have died at the hands of the Australian justice system since 1991 was somebody. They had lives they should have lived. Families they should have grown old with. Decades ahead of them, filled with possibilities and potential, ripped away.
"Instead, their families and loved ones have been left with holes in their lives that can never be filled. Losing a loved one in any circumstance, at any age, is a profoundly traumatic thing. But to have someone taken away so unfairly, and so needlessly, is more than tragic. It is an abomination.
"When the Royal Commission into Aboriginal Deaths in Custody handed down its recommendations in April 1991, I was only a few years old. For 30 years — nearly my entire life — the justice system has kept killing Aboriginal and Torres Strait Islander people.
"And for that entire time, apparently, governments have had more important things to do. They've had everything they need to make the justice system safer. All the hard work was done for them. And they haven't been bothered to take the last, simple step of making those recommendations law.
"When Aboriginal and Torres Strait Islander people win Wimbledon or State of Origin, politicians can't slap us on the back fast enough. But when a First Nations person dies in jail, or in lockup, or in police custody, they're nowhere. For 30 years, they've been nowhere.
"When we try to get answers about these deaths through the justice system — the 'right' way — we're met with silence. When we ask politicians to do their jobs and protect us, we get empty promises.
"And when we stand up against the system that's killing us — like the young men who spelled out 'BLM' with sheets on the roof of the Parklea private prison this week — we're beaten and tear-gassed. Demonised by the media. And abused in the comments sections.
"What's it going to take? How many more coroner's reports and inquiries and commissions and Senate hearings are in our future, piling up like all the ones that came before? How many more rallies and vigils and minutes of silence?
"Will 500 deaths be enough? A thousand?
"How many more times will First Nations people have to pour out our grief, perform our sorrow and lay out the case for our own humanity, before Australia can be moved to change a system that kills us?
"This is a day of shame for Australia. Unutterable shame. And those days are becoming too many to count."
Media contact: Alex McKinnon 0411 829 334
Larissa Baldwin, First Nations Justice Campaign Director at GetUp