"It was based neither on the man himself nor his quality as a player but more on his blunder," the Gunners boss told French television channel Canal+, of his punishment of the former Chelsea player.
"He didn't intend to be malicious, but it put his team under enormous pressure.
"He will remain himself, and it can free him as a player if there is less pressure."
Of the criticism aimed at Gallas during his captaincy, Wenger - who admitted last weekend was "one of the most difficult" he has endured in north London - added: "It was a witch hunt - and everything that he did, even when it was good, was bad.
"In these conditions, the player had no chance."