The Bianconeri spent nearly £50m on the Brazilian pair during the summer, but both have struggled to make the desired impact.
Secco told Gazzetta dello Sport: “I want to begin with what was said this summer, during the market and after Juventus's good start to the season.
“Back then we were all excellent, now we are only more stupid. There is a lack of memory.”
“He is a champion. He was on course to win the Ballon d'Or. Bayern Munich wanted him. The other great Italian clubs wanted him.”
On Melo, Secco said: “Felipe was another prioritised objective of our transfer strategy. We managed to get him. It's paradoxical now to say that we have failed.
“Melo is a regular in the Brazilian national team. He has won the Confederations Cup. He has been judged among the best players of the Confederations Cup.
“No one had any degree of perplexity when he came to be signed by Juventus. I don't have any doubt even now.
“Fiorentina didn't want to sell him. The only way to realise our objective was to pay the €25m buy-out clause. Melo is 26 and he has extraordinary potential. And to be precise he cost €18.5m: Marchionni and Zanetti were also inserted into the deal, two players who were no longer in our project.
“And also thanks to Zanetti's departure it has been possible to re-launch Poulsen,”