Manager Richie Wellens could not hide his anger at full time as Gillingham equalised from the penalty spot to deny his side all three points.
Wilfried Moimbe received his marching orders for an off the ball incident and Tom Eaves dispatched the penalty to ensure the points were shared.
However, the manager was not happy with the decision to award the spot kick.
He said: “I’ve just seen it back and it’s a joke of a decision. Wilfried is fouled first, was spun around so it’s a foul. He has reacted with a punch but surely the foul is first so fair enough you send him off but to give a penalty is a joke.
“He’s made the wrong decision and we didn’t deserve it because I thought we were comfortable in the second half.
“I thought first half we were sloppy, we didn’t pick second balls up and was too deep but we still created five or six decent chances.
“We got in the lead and I thought we were comfortable in the game in the second half. I can’t remember many saves which Johny had to save.
“He made one good save but we had opportunities to get the second but it just didn’t quite happen.
“We could have got the second goal to kill it off but it’s a shocking decision that has cost us.”
Duckens Nazon had given Latics the lead on the stroke of half time. “I thought he was really good today and he was a threat all game,” Wellens said.
“We made a little change in the first half and put him wide because I didn’t think we were picking up second balls in midfield. Duckens was powerful and could have had a few this afternoon.”
One point separates Latics and Tuesday night’s opponents Rochdale.
“We have got to pick ourselves up because we’ve got a massive game on Tuesday,” said the gaffer.
“When you take a hit like this you can either let it affect you or you can look each other in the eye, kick on and come together and get the three points on Tuesday.
“We’ve got no option other than to fight and try and get three points on Tuesday.”