Bentley signed for Tottenham in a £15 million deal this week and Wenger says: "I have no regrets.
"When you have many young players you cannot keep them all. The most important thing is that you develop them as a player and they have a big career.
"At the time the players in front of Bentley, like Ljungberg and [Robert] Pires were better than him.
"He wanted to play more central, in the Dennis Bergkamp role, and I felt at the time he was not ready. He would be more ready today."
Wenger added: "There comes a moment when a player has to play to develop. When you feel that, you have to make a decision to let him go or keep him.
"The fact that Bentley is now a national-team player proves it was the right decision. We deserve praise because we were not stupid and keep the player in the reserves."
Arsenal will receive a portion of the transfer fee - around £6million - under the terms of the deal which took Bentley to Ewood Park.
Wenger said: "At youth level, you are working 90% for other clubs. Some players who are just a little bit short for you go somewhere else but you have an influence on their development.
"When you have an academy of our quality not every player can make it.
"We have two or three players now who have the quality to play for us and some others go somewhere else."