I call on all sorts of people. If I'm working on a big project I may call out "hey Bob, help me with this!" Or if I fall overboard off a ship, I may cry out "First-mate Joe, save me! throw me a life raft!" None of this derogates from the adoration given to God.
Yes, calling on the Mother of God and the Saints is not quite the same as the above, but it is way, way, way more comparable to that than it is to the adoration due to God.
Ultimately, the act of latria given to God is Sacrifice--the Eucharistic Sacrifice is foremost, but also we offer ourselves as "living sacrifices" to God as our ultimate end. We may even offer ourselves to the Blessed Virgin with the intention that she ultimately offers us to God--in those cases, God is still the ultimate object of adoration, not the Saint.