The Rossoneri were held to a 1-1 draw with Catania on Saturday evening, meaning Scudetto rivals Juventus can draw to within two points of the league leaders should they defeat Napoli in Turin on Sunday night.
However, Milan were furious that they did not come away with all three points, with a second-half shot from Robinho having appeared to cross the line before Giovanni Marchese cleared.
Still bitter over Sulley Muntari's 'ghost goal' against Juve at San Siro at the tail end of February, Galliani unsurprisingly feels that Massimiliano Allegri's men have now been robbed of four precious points.
"I don’t have much to say," Galliani told reporters after the game. "I never talk about referees.
"But it’s the second time that the ball has crossed the line. When it crosses the line, it’s a goal - but not for us.
"It’s the second time that it’s happened. First against Juventus and today against Catania. It’s frankly unacceptable.
"In other games they’ve been good at seeing these things but we’ve been unfortunate. I hope that our luck changes and that this episode won’t alter the championship race."
Milan must now switch their attention to the Champions League, though, with the Italian champions set to take Barcelona in the second leg of their quarter-final tie at Camp Nou on Tuesday night.