He told Diario de Noticias: "The current chairman of Real Madrid [Ramon Calderon] was my manager, and I know what he told me and what happens in the end. I have the advantage of knowing the differences between the two clubs [Madrid and United].
"In Madrid, our role was to serve as a kind of wrapping paper. We were to bring Figo, Ronaldo, Zidane to light. But they don't know what recognition and gratitude are there."
On Real's pursuit of Cristiano Ronaldo, Queiroz added: "It's not hard to hold onto Ronaldo.
"Here at Manchester United we can offer pretty much the best conditions. But we can't compete in terms of ethics - because we won't abandon them. Nor is there the promiscuity between United and the English press that exists in Spain, Portugal or Italy.
"Is Ronaldo pressing for an exit? That's something you'd need to ask him."