Commentators clarify that being a "babe" who uses "milk" doesn't mean someone isn't a true Christian. Rather, it describes a believer who is "unskilful" or "inexperienced" in the deeper truths of faith. Like a child who can't chew solid food, they have not yet matured enough to grasp the more profound aspects of Christian doctrine. This is presented as a state of arrested development that needs to be overcome.