There is the narrow point, comprehensively established upthread, that ED is unfair to many lower-income applicants (particularly donut-holers) because it limits their financial options relative to other applicants. There is the broader point, also made upthread, that ED is inherently unfair to lower-income applicants because it’s disproportionately used by wealthier applicants at better high schools, with high-quality preparation and counseling. Many really strong poor applicants simply don’t have the savvy, or the encouragement/support from their schools, to apply early and exploit the better odds, just like many can’t imagine being admitted to a top-tier university, since it’s so far from their experience. And they certainly need more help getting to grips with the ins and outs of financial aid and whether they’re likely to be able to pay for college than middle-to-upper-income applicants from better schools.
This is why the top schools beat the bushes looking for high-quality first-gen applicants (e.g., if you follow Yale Admissions on Instagram, you’ll see that last week they were on the Flathead Indian Reservation in Montana). Rather than indulging a diversity fetish (as some commenters like to argue), they’re trying to counteract the inherent unfairness in the system, unfairness that manifests itself very directly in early admissions, particularly ED.
And this is why, when I hear how ED “enables the schools to pick the students who really love them”, I roll my eyes a little, because what that really means is “enables the schools to pick the students who were in a position to apply early, understood how to work the system and were disproportionately full payers, but yes, had the school in question as their top choice given the odds”.