"Unlike a game of AFL, there are no winners today," the mother of one said in a statement read to the ACT Supreme Court on Thursday.

"There are just a lot of hurt families and hurt children."

Stephen James Porter, 51, left a trail of those in his wake during a decade of despicable deeds.

Between 2009 and his arrest in mid-2020, the Macgregor man committed sexual offences against three boys he coached after meeting them through the Ainslie Football Club or Magpies Juniors in Belconnen.

He used the first to produce child abuse material, raped the second dozens of times, and was in the process of grooming the third when he was arrested.

A raid on his home also turned up a large volume of child exploitation material, which included a video of a 12-year-old boy, at whose home Porter had stayed during an interstate trip, getting changed.

In a victim impact statement read to the court on Thursday by prosecutor Andrew Chatterton, that boy said he had enjoyed meeting Airbnb guests, like Porter, who came to his home from all over the world.

That all changed when police revealed to his family that a hidden camera had been set up in his bedroom

"Since the camera was sneakily put in my bedroom, I've asked my mum and dad to no longer do [Airbnb hosting]," the boy told Porter in his statement.

"I will never, in my life, forgive you."

Mr Chatterton also read aloud a statement from this boy's mother, who admonished Porter for having "tainted" her son's personal space and created "traumatic chapters that can never be erased".

The woman described how her son's view of the world had changed, saying he had become angry at himself for liking, looking up to and trusting Porter, who had been not only a guest but a family friend.

She said she would "never, ever, ever again" have strangers in her home thanks to Porter, who had written "dark chapters of heartache in the lives of children [he] knowingly victimised".

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"You took from us our family's trust in humanity," the mother told Porter in her statement.

"You took from us our son's innocence."

The victim Porter was grooming at the time of his arrest also made a statement, appearing via audio-visual link to tell the court he now had trouble trusting adults and other Australian rules coaches.

"It has made it difficult for me to think about having one-on-one coaches, even though it would be helpful for my development as a player," the boy said.

The victim repeatedly raped by Porter prepared a written statement for Justice Chrissa Loukas-Karlsson, as did his parents, but they did not wish them to be read aloud in court.

After considering the statements, Justice Loukas-Karlsson said some of the victims seemed to believe what had happened to them was somehow their fault.

"Let me make it clear to you that the fault lies with the offender, not with any of you," the judge told them.

"Some of you have expressed shame. The shame belongs to the offender, not to you."

The court also heard evidence on Thursday from forensic psychologist Patrick Newton, who prepared a report on Porter to inform the 51-year-old's sentencing.

Mr Newton, who said he had assessed "somewhere in the vicinity of 3000 sex offenders", described Porter as a "very intelligent" and reflective man, unlike most others.

The psychologist told the court Porter had tried to suppress paedophilic urges from the age of 18, eventually accessing child exploitation material to take his focus away from people around him.

This "sought only to intensify the fantasy", leading to the offending before the court.

Porter, who pleaded guilty to four charges before having his bail revoked at his own request, is set to be sentenced on July 29.

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