Warner was handed a suspension from international cricket for being a part of the group that altered the ball with sandpaper during a Test match against South Africa in March 2018.
"David Warner, a couple of beers into his celebration, mentioned that he used substances attached to the strapping on his hand to accelerate the deterioration of the ball during a first-class match. I looked at Steve Smith who shot a glance that said: 'Ooh, you shouldn't have said that'," Cook, the highest run-scorer for England was quotes as saying by 'The Guardian'.
"Stuart Broad sums it up pretty well and says they got the ball to reverse swing in that Ashes. Why change what you've been doing? Why suddenly use sandpaper? People know what was going on. But it's been the best thing for Australian cricket because they realised it wasn't acceptable. The win-at-all-costs culture they created isn't what the Australian public needed or wanted. They'd gone too far," Cook added.
Cook had retired from the longest format of the game after India's tour of England in 2018.