Why shouldn't innocent infants be part of the kingdom of God? You don't know your church history.
"As the church conquered the pagan world we see infant baptism as arising as a universal practice. In part this appears to be based upon the fact that even in the ancient church there was the concept that baptism was the initiation rite into the community of faith, and infants are born into that community so are baptized. A second factor appears to have been the rise of the understanding of original sin and the belief that baptism washed away the stain of original sin. Third, the ordinances very early were understood as actually conveying grace and accomplishing something spiritually. As early as A.D. 400 Augustine appeals to the universal practice of infant baptism as proof that the church saw infants born with the stain of original sin. We find explicit mention of infant baptism as early as Tertullian around A.D. 220. Tertullian mentions the practice in conjunction with sponsors who would aid in the child’s spiritual training. I would assume that this is the origin of the practice of godparents."
