The reactions you get from people or certain circumstances shouldn't change you negatively. If you a generally a good person, then be good. If it was your desire to aid them in the past, you should by all means do what you must but, perhaps with a price (by price, i don't mean it must be money) and a little much stressful this time.
Should be I guess. But OP had a bad experiences. Though we know resentment is corrosive, its not always like that. But its not our cup of tea to judge them since we arent on his place.
Apparently, I think OP still cares and will definitely do the right thing. Past is a past and maybe they learn the lesson when the things they noticed got changed too. Its a shamed that respect isnt done at the beginning and to end up being in the same foot but you already did a horrible judgement.