The Ghana international was sent off for elbowing West Ham’s Aaron Cresswell on 17 minutes, before Michail Antonio and Cheikhou Kouyate scored for the home side in the 58th and 85th minutes.
“Jordan has no excuse to do that,” Garde said. “I know that he knows that.
“He will be suspended now. Today, it was a big blow for the team. The 10 men fought very hard, and I’ve nothing to reproach them about.
“It’s a big mountain, we started well. We were well in the game. I wouldn’t say we controlled the game but it was 11 versus 11.”
Villa had a penalty call ignored by referee Jonathan Moss in the 11th minute when Gabriel Agbonlahor’s cross appeared to have struck the arm of Antonio.
“I was feeling good about the team, like the previous weeks,” Garde added.“Then the penalty is not given, then there’s a stupid red card.
“It’s the way we lost. In that match – 11 v 11 for 90 minutes, am sure we would have been getting something at the end.”
Rock-bottom of the league standings with 13 points after 21 matches, Villa will host Norwich on Saturday.