I understand your feelings and share them which if why we only donate to places that *give away* their clothing. They cut out brand labels (but not sizes) so they can't be resold. Some of them "card" people by asking to see if they have a food stamp, WIC or state health card.
That said, most people I know who are truly low income can't afford to shop at Goodwill. Its actually very expensive as their goal is to make $$ to support their other programs. They are very up front about NOT being in the line of providing inexpensive goods for families!
Ds1 (2006). Ds2 (2010). Ds3 (2012).