Justice Soraya Ryan said violence appeared to be a "pastime" for the trio who failed in their bid to have their charges dismissed at their Brisbane Supreme Court trial on Tuesday.
"The evidence suggests that they were bored and idle ... and had ... a very casual attitude to violence," she said.
"They viewed it as some sort of pastime, something to do on a night out."
Defence barristers for the trio submitted no-case applications, arguing there was insufficient evidence to continue the trial which has entered its second week.
The three teens had pleaded not guilty to manslaughter and two counts of grievous bodily harm at the judge-only trial.
Five boys - aged between 15 and 18 at the time - were arrested following Jack's death in December 2019.
Jack was stabbed in the heart during a fight between his group and five teens at Surfers Paradise, the court was told.
After considering the defence's arguments, Justice Ryan ruled the prosecution did have a case.
She backed crown prosecutor Todd Fuller's argument that death or grievous bodily harm could be a "probable consequence" of a fist fight.
"The question of the no case is whether it would be open to the jury acting reasonably to reach that conclusion, not whether they had to reach that conclusion but whether they could. I find that it could," Justice Ryan said.
An assault with punches and kicks may well cause fatal or grievous injuries, she said.
"This is particularly the case when persons move as a group."
Five teenagers ran down Surfers Paradise Boulevard in pursuit of Jack's group before stopping them outside Paradise Towers apartment building and starting a fight, the court has heard.
A 15-year-old had a knife tucked in his pants, stabbing Jack once, piercing his heart, and another 17-year-old boy twice - puncturing his lung and causing internal bleeding - during the altercation.
Defence barrister Gregory McGuire - representing one of the teens - told the court that the fight between the two groups was consensual and his client did not know a knife would be used in the clash.
But Justice Ryan said evidence indicated Jack's group was given "no choice other than to respond".
"In my view the CCTV footage showing movements of defendants ... could allow a jury to conclude that the common purpose was to get into a fight whether Jack Beasley and his group agreed to it or not," she said.
"I find that the prosecution does have a case to answer in the case of each defendant."
A teenager - who was 15 at the time of the incident - this month pleaded guilty to murder and two counts of committing malicious acts with intent.
Another teenager - who was 17 at the time - pleaded guilty to manslaughter and two counts of grievous bodily harm in April.
Closing arguments will be held on Wednesday.
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