Choosing your battles

I have a relative, let's call this relative Mr/Mrs Racist, who is quite relaxed about saying things at social functions that aren't normally contemplated in our milieu, much less spoken aloud.
You may have guessed that this relative's bent is making fairly racist comments. But his/her musings aren't limited to race. Mostly anything s/he finds different or unknown is fair game (hairy legged feminist lesbos, for example).
Clearly I have a major beef - Porterhouse steak sized - with this kind of view. However, I also believe in his/her right to say it. I am of the firm belief that enlightenment comes from a robust exchange of ideas and experience.
But I also believe I have a moral obligation to challenge a view which I believe is destructive and dangerous and not supported by fact.
I have made gentle comments to this effect. Such as pointing out the use of certain phrases is considered offensive by the people to whom those terms refer. But my comments appear to have fallen on deaf ears (it seems at 33 I'm not in possession of enough life experience to make any kind of political or philosophical judgement for myself - those things are probably best left for my husband to decide for me).
So my quandary today is what to do? Make a bigger fuss and risk complete alienation and familial discord without changing anyone's mind, or keep chipping away slowly but surely on my one-woman campaign of enlightening this relative, or at least offering another point of view to consider?
I am thinking of making a donation (as a Christmas present) to a charity organisation for the group of people about whom this relative was recently spouting, in a bid to gently, but firmly reaffirm my dislike of the views expressed.
I'll post on what happens (if anything!).