shouldn't we come to a point that we don't sin?
The problem is that people sin in so many different ways, especially in ways that they don't even realize they are sinning. That said, people have to learn how to love, because so many times people have never taught them. It's like people who spank their child, scientific research has shown that it's actually a bad thing to do that because it tends to make children more prone to aggression and physical violence later in life, but some people are so focused on the idea that "spare the rod, spoil the child" must be taken literally, that they are actually doing damage to their children, even if they might be doing some good with it. "Spare the rod, spoil the child" simply means make sure to discipline your children when it is in the child's best interest to do so.
Also, a lot of things in the Bible are not understood, both by individuals and denominations. This makes it so that people continue to sin until God frees those people up by giving them understanding about what certain Scriptures really mean. It often takes time for people to learn things, just like it often takes time for a child to learn how to do math correctly. If Jesus is our example, then are 90% of christians not healing the sick and raising the dead? Why aren't crowds following us around to hear the gospel? Why do so many christians have an attitude and make non-christians want to throw up by their horrible witnessing strategies? Why doesn't everyone feel loved when they are around christians?
Why? Because Christians either don't understand or don't know how to do these things. God laid the earth's foundation with his wisdom, and put the heavens in place by his understanding (Proverbs 3:19). Even if we are "free" in Christ and don't have to sin any more, we still have to learn how to walk the right way, and that takes time. "
2Do not conform any longer to the pattern of this world,
but be transformed by the renewing of your mind. Then you will be able to test and approve what God's will ishis good, pleasing and perfect will." Romans 12:2. Paul also said: "
2I gave you milk, not solid food, for you were not yet ready for it. Indeed, you are still not ready." 1 Corinth. 3:2 (Also- Hebrews 5:12-14). So we know that there are different levels of understanding in God, and these things affect how we will act.