Really interesting discussion, I found everyone's thoughts interesting. Re-reading absentgrana's original post, I think Greatnan's solution is the wisest.
But I quite admire the host for two reasons. First he is making it clear he does not want guests to waste money on presents (presents for '0' birthdays tend to be either expensive or silly) and second, he had the guts to name a charity he believes in, maybe knowing it would not be universally popular. To his credit, he did not know if or who donated, or how much. Thus leaving his guests free to follow their own consciences.
However the principle absentgrana identifies goes deep. How far do we let our own beliefs influence our lives and actions?
I am nominally an Anglican Christian, and I do believe in a loving, creator God, but I have a problem with institutionalised religion and its politics (with both big and small 'P's) and pettiness, which makes me a non-churchgoer. Pity, because I love the architecture and music in great cathedrals.
Over the years I can no longer believe that there is only one way of understanding the great issues of Life (why are we here? what are we here for? do we have a purpose? etc etc)--and Death (is it The End? etc etc). I am interested in the beliefs of many different cultures, as well as the monotheistic religions, Buddhism and the Tao. This is why I took a degree in Medical Anthropology in my 50s--to help me explore different peoples' ideas about 'health', life and death. And I'm still exploring what I believe!
But I would draw the line at donating to a charity whose aims I had thought about, but was opposed to. And I have problems with proselytising too.
Maybe I should change my username to 'confused.oap'