The United chairman insisted it was time to let Blackwell go earlier this week and not before, and also revealed how difficult it was to sack a man he respected so much.
"In the course of a 40-year career in football administration I've had to dispense with the services of a lot of managers and believe me, it doesn't get any easier," Bates said in his programme notes ahead of Leeds' home game with Birmingham.
"Kevin is a thoroughly nice guy, but it was time for him to go. To those fans who said he should have been sacked after Cardiff, I would say you don't make fundamental decisions after one bad game.
"Kevin did as good a job as he could and we should always be grateful for that, but it is time to move on and to those who say he was not given funds to improve the team I would point out that the money spent on players since my arrival has totalled £7.144million, with a net expenditure of £2.487million."