The Giants were down to one man on the interchange bench before half-time and sat 17th on the ladder going into the game, but piled on 13 goals to one after quarter-time in the Demons' worst performance for the season.
The loss leaves Melbourne in 17th with four wins for the season, and facing a trip to Patersons Stadium to take on West Coast next week.
Roos, who chose not to address the players after the game for fear of what he might say in the heat of the moment, nevertheless delivered a blunt message at his post-match media conference.
"If you can't keep up, you don't stay on the senior list," he said.
Roos said the team's performance was simply not up to AFL standard on Sunday.
"I'm embarrassed. Players can speak for themselves, but I mean you have to be," he said.
"Take nothing away from the Giants, but they were three down.
"Whether guys are tired ... it looks like they've put the cue in the rack (for the season) and thought 'four wins is good enough for us. We've improved'.
"Today was not an AFL standard game of footy from us."
The Giants had just 67 interchanges for the game but won the last three quarters.
"They outran us, which I think tells you about their mentality compared to our mentality," Roos said. "They outran us and outworked us with 19 players."
The Demons coach said there was no lack of intent to move the ball quickly and aggressively, but the skills were so deplorable it became impossible for the Demons to go forward with any system.
"There was nothing positive to come out of today, but there were plenty of negatives so I chose not to speak to them at the end of the game," Roos said.
Roos said the task of re-establishing Melbourne was always going to take three to five seasons and lifting clubs from the bottom was not made any easier with the introduction of free agency and two expansion clubs.
As he spoke, he sounded like a Monopoly player who held only Old Kent Road and Whitechapel Road after every property had been bought.
Despite kicking just three goals (from 19 scoring shots), Roos said he wished fixing the problem was as easy as changing the game plan.
"I wish it was that simple ... [if it was] I'd happily change [the game plan]. You are assessing yourself as a coach all the time, there is no question, but just the simple errors ... just incredible," Roos said.
"If you have got an inability to hit targets, it's really hard to implement a game plan because you just can't execute the most basic skills."