I think giving to charities should be a personal choice and no one should feel forced into it.
However I must just say, I had supported a particular charity for years, not in a huge way but I did collecting boxes for them, raffles, donated a bit and bought gifts from them.
One particular year my husband had an accident and couldn't work for the next few years, all tht time the charity pestered. I wrote a letter explaining my situation , said couldn't afford to donate and couldn't 'Fund-raise' but would still be happy to buy Christmas cards from them etc. I had no reply and in fact they cut all contact, I never received anything else from them, no 'Thanks for your previous help' So when we got back on our feet I vowed that charity would never get another bean. Their loss.