The Frenchman said deliberate fouling was more harmful to the game than the alleged dive by Arsenal striker Eduardo da Silva which is being investigated by UEFA.
"I have seen a player who plays on the pitch only to make fouls. For me, this is a point that is more urgent than diving," British media reported Wenger as saying.
Eduardo was scrutinised after last week's Champions League qualifying victory over Celtic, having allegedly dived to win a penalty which he then scored to set up a 3-1 Arsenal victory.
"The players who are never punished, who get out of the game without a yellow card. I think it is more anti-football than a player who did what Eduardo did," Wenger said.
United inflicted a first defeat of the season on Wenger's side after two second-half goals cancelled out Andrei Arshavin's strike.
In a competitive match, six yellow cards were shown to Arsenal players and three to United.
The game ended with Wenger being dismissed from the touchline for kicking a water bottle, a decision the Premier League referees' body later acknowledged was an error. Wenger is to receive an apology.
"Look at how many deliberate fouls some players get away with. That's a bigger problem because it cuts the flow of the game. And people pay to see football, not free kicks."
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