And sometimes, certainly, that is true. Some of the prayers to saints, are meta-prayers: they are prayers for prayers.
But that's a misleading claim, for many of the prayers, particularly those to Mary, are not just requests for prayers.
Consider this prayer to Mary, provided at the conclusion of the pope's encyclical of earlier today:
"Holy Mary, Mother of God, our Mother, teach us to believe, to hope, to love with you. Show us the way to his Kingdom! Star of the Sea, shine upon us and guide us on our way!"
And that's a fairly tame, ecumenical version. Consider this:
Most beautiful Flower of Mount Carmel,
Fruitful Vine, Splendor of Heaven,
Blessed Mother of the Son of God,
assist me in this my necessity.
O Star of the Sea,
help me and show me herein
that you are my Mother.
Holy Mary, Mother of God,
Queen of Heaven and Earth,
I humbly beseech you
from the bottom of my heart,
to succor me in this necessity;
there are none that can withstand your power.
It's ironic that those who deny the irresistible nature of God's saving grace, thereby implicitly denying God's omnipotence, affirm the super-omnipotence of Mary, while worshipping her in a way that clearly violates the first commandment.