Having to abbreviate your quote to make this doable.
To save a long answer (edit:although I've ended up writing a long answer anyways) explaining just how wrong you are in what you've said below, do you think, if a non-white person living in a white majority society were to be asked: Do you think white people should (a) think less about race ; (b) think more about race?, the answer would be (a) or (b)?
It's not about "fretting compulsively over every last gesture or syllable". If only we were anywhere near that point in terms of awareness of everyday racism! It's an absurd use of language when structural racism is basically treated like it doesn't exist on a day-to-day basis, and when there are still masses of very obvious things that people get wrong all the time. Just one example: your use of "blacks" above should clearly read "black people" - it's a glaringly dodgy use of language**. And I'm not getting at you specifically - merely making the point that any white person who thinks they should be thinking less about race rather than more needs a reality check, I'm afraid.
My diagnosis of the major problem (which may be wrong, but hey) is simple - society is still super-segregated, and when there are mixed groups that hang out together, they are overwhelmingly majority white and therefore the non-white members are frequently silenced about the casual and structural racism that is going on
all the time. Because white people don't feel comfortable with it. So white people don't often talk to non-white people about racism in a situation where the truth can be told without any comeback.
I guess I have to add a personal disclaimer which explains where I'm coming from - had I not for the past two decades had a best friend who happens to be black, I would be a lot fucking dumber about race than I think I am now, cos talking to him over the years made me realise how little I knew and how much I had to learn. One sees a constant barrage of racism if one is hanging out all the time with someone who's experiencing it, including from white people who can't deal with interrogating the racism they've picked up from hanging round with lots of other white people.
That's just the truth - most people turn a blind eye when the issue gets more complicated than just not using racial epithets. To choose one blatant example - when the issue is around not being admitted to a venue because of one's colour - 2010s London, not 1975 Johannesburg btw - most people pretend it's not happening, or that it is the fault of the person refused entry for some unspecified reason. So, do we need to think more or less about racism?
As to the caste system, I'm not sure to what extent this is true, but I'd need to read more on the subject.
** and I know the term is still widely used, but it's 2012 and we should be talking about black people, gay people etc etc, not about 'blacks' and 'gays', given that the very substance of discrimination and prejudice is to treat others as though they are not actually human, essentialising them out of existence.
I don't know how useful this Witchfinder-General approach to subconscious racism really is. Taken to its logical conclusion, it can lead nowhere but a sort of psychic paralysis whereby you fret compulsively over your every gesture and syllable. And moreover, surely it's the one thing (short of outright white supremacism) that's guaranteed to make you think about non-white people differently from how think about white people, which is a bit of an own goal, isn't it? That's not an argument for blithely going through life pretending racism doesn't exist or has been 'solved', it's just an argument for not obsessing over IT to an extent that it becomes self-defeating.
I have no doubt the caste system was further entrenched by the British in India but I'm pretty sure it was racialized long before any white people turned up. There's always been a correlation between being high-caste and pale-skinned and between being low-caste and dark-skinned.