From the Catechism of the Catholic Church:
1250 Born with a fallen human nature and tainted by original sin, children also have need of the new birth in Baptism to be freed from the power of darkness and brought into the realm of the freedom of the children of God, to which all men are called. The sheer gratuitousness of the grace of salvation is particularly manifest in infant Baptism. The Church and the parents would deny a child the priceless grace of becoming a child of God were they not to confer Baptism shortly after birth.
1251 Christian parents will recognize that this practice also accords with their role as nurturers of the life that God has entrusted to them.
1252 The practice of infant Baptism is an immemorial tradition of the Church. There is explicit testimony to this practice from the second century on, and it is quite possible that, from the beginning of the apostolic preaching, when whole "households" received baptism, infants may also have been baptized.
1253 Baptism is the sacrament of faith. But faith needs the community of believers. It is only within the faith of the Church that each of the faithful can believe. The faith required for Baptism is not a perfect and mature faith, but a beginning that is called to develop. The catechumen or the godparent is asked: "What do you ask of God's Church?" The response is: "Faith!"
1254 For all the baptized, children or adults, faith must grow after Baptism. For this reason the Church celebrates each year at the Easter Vigil the renewal of baptismal promises. Preparation for Baptism leads only to the threshold of new life. Baptism is the source of that new life in Christ from which the entire Christian life springs forth.
1255 For the grace of Baptism to unfold, the parents' help is important. So too is the role of the godfather and godmother, who must be firm believers, able and ready to help the newly baptized - child or adult on the road of Christian life. Their task is a truly ecclesial function (officium). The whole ecclesial community bears some responsibility for the development and safeguarding of the grace given at Baptism.
1282 Since the earliest times, Baptism has been administered to children, for it is a grace and a gift of God that does not presuppose any human merit; children are baptized in the faith of the Church. Entry into Christian life gives access to true freedom.
My own take on this:
It is disingenuous to say that Christ's Sacrifice is all-sufficient and there is nothing we can do to merit salvation and then say that we must believe in order to be saved. If there is nothing we can do to affect our own salvation, then even our own faith is moot and Christ died for all... period. As it is, Baptism is the beginning of our life in faith, not the culmination of it. From there, we have our infancy in the Family of God and God, through His Holy Spirit, will raise us.
Just as you don't take away the free will of your children in raising them, there is no conflict between infant baptism and the Christian's duty to conform his life to Christ. We might just as soon say we had violated a child's free will in calling him into this world at his birth.
Baptism is an ordinace where a believer publicly professes their belief in Christ. In every Biblical instance, Baptism always follows professed belief, and belief always comes after the Word.
You ought to stick with what the Bible says, and not what the Catholic church says.
Go straight to the source.
>>It is disingenuous to say that Christ's Sacrifice is all-sufficient<<
Then you clearly don't accept the Bible as truth:
"But he said to me, "My grace is sufficient for you, for my power is made perfect in weakness." Therefore I will boast all the more gladly of my weaknesses, so that the power of Christ may rest upon me. - 2 Cor 12:9
To suggest that Christ's sacrifice onthe cross wasn't sufficient, and that we somehow have to meet him half-way in order to earn our salvation is an outright lie that has no basis in scripture.
Salvation is appointed from before the foundation of the world, a gift to God's elect (read Ephesians). Not everyone will go to heaven, in fact few will (Mt. 7:14)
>>even our own faith is moot<<
Faith is the product of salvation, not the cause of it. God calls, and we respond - not the other way around.