So for those that don't baptize infants, I think there's often a misunderstanding -- shoot, also even among those that do it -- about the outcome and expectations around infant baptism.
So to get clarity about this, there's a thought to ponder: is "becoming a Christian" the same thing as having one's sins forgiven before God?
Or what about this: is the church a community of Christians, or is the church a community of those who have been been forgiven and redeemed by God? Is there a difference?
So I totally respect the simplicity and consistency of those who say that only those who make a credible profession of faith should be baptized, be a member of church, and then to be considered "Christian". They are trying to strongly emphasize the importance of the act of consciously turning away from the world and following the way of Christ. They emphasize the church as "the redeemed by God".
However, we live in a particular modern and rather individualistic mindset, compared to many Christian who lived in the past. The above way of seeing salvation and Christendom makes certain assumptions, and historically there have been different assumptions that were dominant. We don't have to agree, but we should try to put ourselves in their shoes.
So here's the idea: historically, the concept of baptism, plus the concept of being part of a specific church congregation, plus the idea of being called "Christian", have been all very closely tied together. For many (arguably most?) of them, their identity as a Christian was derived from being part of a church, from being a member of a Christian community.
If children are in worship, they learn from their Christian parents and from Christian leaders and teachers, and are associated with those that profess Christ, so even without their assent they are already called "Christians" by those around them and by those outside the church looking in. So in this context, you can think of baptism as merely saying, "yes, this child is part of this community". And in fact, many church traditions and denominations ALSO contain prayers or even confessional statements that look forward to this "presumption", as it were, that their children will one day strongly confess that which they were baptized into.
So okay, for a Bible passage that captures this idea, consider the description of the "kingdom of heaven" in the parable of the wheat and weeds (in Matthew 13). In this passage, a field is seeded with wheat, but also there's a bunch of seeds from weeds. So as soon as it starts growing, the workers are like, "Oh man, look at all these weeds! Should we pull them up?" But the owner says (paraphrasing a bit), "No, at this stage, you might uproot the wheat accidentally. Let both grow together until the harvest, once they show their fruit, it will be easy to distinguish them." If God is the "owner" in this analogy, than we "workers" wait for God's harvest, and we don't start trying to pull out weeds before then.
All it takes to be a member of a church, is to make an outward profession of faith and to be baptized. This is a really low bar for a "requirement", we KNOW that some people who say this don't understand what they're saying, or don't actually believe it. This is not fundamentally threatening to the church, and this is not fundamentally different from what happens in infant baptism. A Christian church should not be "weeding out" people -- even infants! -- who might one day end up "turning away" from the faith. Baptism and church membership are given generously, all alike are taught and cared for equally, until a person explicitly separates from the community, or is kicked out over egregious unrepentant sin (an example of that "fruit" mentioned before).
So whether you practice this or not, it should surely be helpful for mutual understanding, to avoid uncharitable accusations or hostility from ignorance. But I would also invite you to consider WHY large parts of the Church have held this view, up until the present day. Personally, I greatly appreciate the "wide open invitation" that such a doctrine implies, and I think it's certainly consistent with the biblical picture of the Church -- the Kingdom of God -- is welcoming to people at all stages of maturity, insight, understanding, and sanctification.