Sergeant Christopher Hand has given evidence for a second day in the inquiry into the death of Kumanjayi Walker, who was shot and killed by a policeman in Yuendumu in November 2019.
Sgt Hand said he understood and appreciated that some people in the community held the view that police should not carry sidearms.
But he said police needed their firearms to protect themselves and other members of the public.
He said they also acted as a deterrent to potential offenders.
"Everyone has views about policing and how police do things," he said.
"But for any community, whether it's an Indigenous community, or an urban community or a small town in country South Australia to suggest that police shouldn't be armed with a side arm, I find that incredible.
"Because there are guns in the community and Yuendumu is the same.
"They would expect us to protect the community, that is our job."
In earlier evidence, Sergeant Lanyon Smith also defended the carrying of guns in the remote town, even though he had never needed to draw the weapon.
He said the presence of guns in remote communities also meant police should be armed.
"If a community member has a gun, we need to have guns as well," he said.
The inquest in Alice Springs is exploring 54 issues related to the life of Mr Walker, 19, and the actions of police before and after he was killed.
The Warlpiri man died after Constable Zachary Rolfe shot him three times during an arrest attempt in Yuendumu, northwest of Alice Springs.
Const Rolfe was later charged with murder but acquitted of all charges after a Supreme Court trial.
The inquest continues.