Gurm I agree it's frustrating. We should petition Apple to allow us to do this...if we can't get through via support, maybe we can find engineers at Apple on LinkedIn or similar and try to make them aware of this issue. Most people are under the impression that dithering is not perceptible by humans, but as we know, it can still have an adverse affect on us.
I don't use OS X and I don't know much about Kexts, so one possibility could be to use Rent-A-Coder or something like that, and maybe pay someone that has the experience to make one for us (and make sure we get the source code). I'd be happy to chip in for this for our community. As JTL mentioned in another thread, disabling dithering is a competitive advantage for the Amulet folks, unrelated to eye strain.
The fact that it can be done on OS X is very encouraging. I don't know if iOS is known to dither, but it's very locked down, and I strongly suspect it's not possible to disable or alter without jailbreaking.