For newborn medications (Hep b, vit k, erythromycin, RSV vaccine) the doses are all standard regardless of the weight. Requiring a weight to be entered prior to pulling/administering the medications interferes with the 'golden hour' after birth where the newborn is not supposed to separated from the mother and goes against best practice recommendations.
Not all drugs require a weight to calculate the dose, in fact only about 20-30% require the weight to determine dose so it seems it would make more sense to have the weight entry requirement ONLY turned on for those medications that require it.