I don’t think anyone teaches that, though I too would find a teaching such as that as dangerous.However, to someone who believes that baptism was meant to follow an individuals own response to God at an age where they understand what they are doing, it is easy to look at the danger the doctrine of infant baptism may present when one who was baptized as an infant proclaims that he is now a Christian and that is all he ever has to do to be right with God. In a sense it is like a OSAS by infant baptism.
My point was not to create a discussion on baptism, but just to point out that generalizations about what Protestants believe are generally inaccurate, generally speaking.