Circumcision and Baptism

I have heard some people say that baptism is like circumcision, and since you don't have to be circumcised anymore, you don't have to be baptized anymore, either. I always want to ask them if they have a starter in their car, and if they do, then, why? the starter is just like the old-time hand-cranks, so if you don't need a hand-crank anymore, then you must not need starter, either.
Realistically, the reason that circumcision was required to be a Jew, but not required to be a Christian has a lot to do with the fact that, although Christianity grew out of Judaism, they are two different religions. And, yes, there are many times in Scripture where it compares baptism with circumcision, it is pretty clear that while circumcision is a requirement for a man to be a Jew, baptism is a requirement for anyone to be Christian. Isn't it convenient that we know have something that women can do, too?
Let’s look at circumcision first: This was actually one of the earliest commandments, God told Abraham, long before He gave Moses the law, to circumcise all the baby boys among his descendents. Now, Moses, having run away from Egypt into Ethiopia, but now having seen the burning bush, and is going back to Egypt to set his people free, gets partway back, with his Ethiopian wife, Zipporah, and God demands that Moses’ son be circumcised—God seems to be prepared to kill Moses over this. Keep in mind that this is totally foreign to Zipporah (it probably seemed completely barbaric to her), and Moses, not really having been raised as a Jew, himself, never really pressed the issue with her, but now that they are away from her people, and heading back towards his people, God wants Moses’ family to be right. Obviously, this was an important commandment if God was willing to kill Moses over it. Keep in mind, also, that Moses was in a unique position; he was raised as the son of Pharaoh’s daughter, so he knew the palace, and, even though he may not have the most favor of the current administration, they knew him, and probably thought of him as family (the black sheep of the family, no doubt, but he could make requests that ordinary Hebrews would be killed over). So God has this individual that fits the current situation perfectly, except for this one little thing, and God is ready to kill him, and raise up another one to take his place, unless he circumcises his son.
Now, baptism is generally thought to have begun with John the Baptist. Of course, John was sent to prepare the way for the Christ. Now we have four different accounts of the Great Commission, each of them at least a little different, but both Matthew and Mark agree that baptism is part of the Great Commission. That makes it sound like baptism is pretty important, too. Now, in Colossians 2:11-12, Apostle Paul makes the comparison between circumcision and baptism. In Romans 2, Apostle Paul attempts to explain why, in this new covenant, that physical circumcision means so little, but the circumcision that matters is the circumcision of the heart—which would have to be circumcision “made without hands.” In First Corinthians 7, Paul also explains that, in Christ, it really doesn’t matter whether one is circumcised or not, what matters is obedience—keeping the commandments. We have already established that Jesus commanded baptism in the Great Commission, so any attempt to disavow baptism is really an attempt to disavow what Jesus said.