I also experienced financial disadvantage growing up (working to help supplement rent payments)... However, I did not fill out the disadvantaged status blip. I did not want to seem that I was "whining" at the time. I did talk about my experience in my personal statement and "overcoming adversity" questions. I also recieved FAP. Was not filling out the disadvantaged blurb on AMCAS a mistake? hmmmm.... any thoughts?
To be hosest I think someone is just bitter about not getting in. Look maybe the disadvantaged status didn't work out for you but that is not what kept you out of medical school.