I have a bit of a problem with this--the step-parent isn't otherwise on the hook for a child's expenses in other aspects of life. For example, when child support is calculated, it is only the parent whose income is considered. The income of step-mothers and step-fathers is not considered. Why is it suddenly considered when calculating what a student can/cannot afford for college, particularly considering that the student is technically an adult at this time.
FAFSA is a bit of a sore spot with me for other reasons. I have a niece that has been completely cut off from financial support from both parents. (She has done nothing to deserve this--she just has crappy parents.) In fact, they often want favors from her that cost her money personally. Her grandparents pay for her medical and vehicle insurance (on the vehicle they bought her). Fortunately, she graduated within the top 10% of her class, so most of her tuition, fees, and housing are covered, but not entirely. She works at a grocery store near her campus to help cover her gas and other necessities.
FAFSA forces information on parent income, even though she is essentially independent.