The only possible difference is adding white people (or some other separate group) to the "discriminating against" set. And the combination of that precedent and intersectional politics makes even those equivalent as soon as you start adding more non-asian subgroups to the set of disadvantaged minorities.
For example, the white population at Harvard is overly culturally homogeneous. It would legitimately be a significant benefit to their cultural diversity to get some more rednecks in there, using some suitably more specific definition with regard to income, hometown urbanization level, etc.
So if you want to discriminate against a specific group, easy -- just enumerate a bunch of underrepresented groups that don't include them and give them each a bonus. Any given applicant outside of the target victim group is likely to be in one of them.
> So basically the bottom 10% of asians get exluded.
That's just because you're using convenient numbers. If the merit-based numbers would have been 60% asian (e.g. because Asia has a couple billion people who would all like to go to Harvard), you do have to exclude half of them to get them down to 30%.
Especially in the latter case, the effect on asians is indirect and attenuted. For example, say Harvard would have been 60% white, 30% asian, and 10% underrepresented minority. You can double the representation of disadvantaged minorities by reducing the asian representation from 30% to about 27%. So basically the bottom 10% of asians get exluded.
What is instead being alleged here is that Harvard exluded more than half the Asians that otherwise would have been admitted.