I have seen quite a few whites here... as far as their motivation I cannot generalize...
however I would imagine you have all of the above...
the comfortable background white upperclass cat with the guilties who really wants to help...
and the person who comes simply cause they don't have to pay taxes and can live free and stack up their dough in the same position? Non-profit or church based pay no taxes if american citizens...
or they could suffer from the Tarzan complex...
or the Christian complex of we must save them...
or they could just be a decent cat who's up on the real...
it depends.