i'm not a native English speaker so I could err however I do know one song called 'I ain't too proud to beg' which tells me that the notion of 'pride' and 'being proud' is very much applicable to the situation of aid refusal, and KLAPA mentioned charity which is essentially aid

in Russian culture a personal stance on aid acceptance or refusal is judged on the basis of possession of pride quality by the aid recipient

in such a situation 'как тебе не стыдно?' is completely wrong