There could be a great many reasons, and most of them suggest that visual, auditory, etc. learners are not the problem. The research on differentiation based on learning modalities is unequivocal - it's a waste of time or worse. If children ask the teacher to repeat directions, for example, it is likely because they did not understand what parts of the directions to attend to in the first place, do not have a written job aid for reference later, and so on.