Bennett had been competing with goal scorer Andi Weimann for possession of the ball who had fouled the left-back.
Williams and Weimann had sandwiched Bennett but as the midfielder tried to get back up, there was a kick-out from the former Cardiff defender.
The act did not go unnoticed but it only merited a yellow card in the eyes of the referee John Busby.
Asked by Wigan Today on if he thought it was a dismissal for his own player, Richardson said: "When you saw Joe Williams throw himself on the floor three or four times after that probably not, no!"
Bennett was substituted at half-time for Thelo Aasgaard to avoid going down to ten-man after the player was walking a tightrope.
"I thought with the game panning out the way it was, it was the right decision.
"It was very much a counter-attacking game, and when somebody’s on a yellow card, with the heat and everything else to consider, you try and make proactive decisions.
Williams was in amongst it for City and also collided with Republic of Ireland winger James McLean, with both players showing a desire to win.
Richardson has had the pleasure of working with both players having been assistant to Paul Cook at the DW Stadium before Williams made his way to the West Country.
Richardson said: “I’ve worked with both of them...both very emotional characters, both desperate to win for themselves and the team.
"And I think that’s all that it was, a desire to do well and help their team. They’re both very similar...you just need to try and keep them both apart..."
Wigan felt aggrieved that they hadn’t been awarded a penalty when they were trailing to Weimann’s opener.
Home fans and the team protested that Tommy Conway had handled the ball when defending from Jack Whatmough’s header from a McLean corner.
"I thought we could have had a penalty,” he said.
"Listen, teams do what they need to do to try and win games, we do some things that we need to do to try and win games.”