FHA used to have strict maximum loan limits. In the early 80s, the cap was less than $100k. It may have been nearly impossible to get a loan with less than 10% down if you were shopping for a high-end house.
My argument is, 20% down is not equally hard for everyone, it’s much harder for a low-income household than for a high-end household. It should be okay to give 3% down loans to low-income homebuyers.