McNeil, a labourer, allegedly boasted he was a mixed martial arts fighter before punching Mr Christie in the face as he shielded the other young men.
McNeil has been charged with causing grievous bodily harm, assault occasioning actual bodily harm and two counts of common assault.
Through his lawyer, McNeil told the court the first group of young men was trying to sell him drugs and he acted to protect his girlfriend who was with him at the time.
He was unable to explain his actions towards the Christies, police facts tendered in court said.
NSW Premier Barry O'Farrell said he was "appalled'' at the incident, which occurred on the same street on the late-night strip where king-hit killing victim Thomas Kelly was targeted in 2012.
The incident also occurred just weeks after 23-year-old Michael McEwen was critically injured in a drink-fuelled bashing at Bondi Beach.
"There's no doubt the Christie family today, like the McEwen family, like the Kelly family, are suffering in ways families should never have to go through,'' Mr O'Farrell told the ABC Radio on Thursday.
"I don't understand the violence lust or the violence rage that exists out there below the surface.''
But he said the number of assaults at Kings Cross had reduced by one third due to a government crackdown in the precinct in the last year.
"That's of no comfort to the Christie family this morning but equally, the slogan being put forward by my opponents - 1am lockouts, 3am shutouts - is of no comfort to someone who was assaulted at 9pm,'' Mr O'Farrell said.
"We need to crack down on the problem venues, we need to crack down on the problem precincts.
"That's what we're doing and we feel we're making progress.''
- AAP
