The iZombie writer has been fired from his final project for the company after publicly criticising its business ethics.
"I don't know the writer Chris and it certainly would have helped if I could have talked to him or if he had reached out to me," said Lee at the Los Angeles Festival of Books.
"I didn't know he felt that way so it was surprising to see that. It seemed odd to me as a creator, I would not publicly state I have a problem with the company that's paying me to do work for them and I'm going to quit after I do this one project. It would seem wise to me to wait until you finished the project to voice that complaint.
"You have to imagine from our perspective, for our own internal morale, what does it say for a company to hire somebody who's that vocally against our principles and yet we're still paying them. From that standpoint, it doesn't make any sense."
DiDio added: "As far as I'm concerned, he made a very public statement about not wanting to work with DC and we honoured that statement."
Roberson criticised DC on Twitter, saying that following his completion of an arc of Fables spinoff Fairest, he would no longer work for the publisher.
DC responded by telling him that his Fairest contribution would no longer be required.
Co-pubishers DiDio and Lee also addressed the controversy over Before Watchmen and Alan Moore's opposition to the project during the festival panel.
> Chris Roberson speaks out on DC Comics sacking