That's what this is really all about, isn't it? That Latinos and Blacks should be present in higher numbers for social equality reasons?
Everyone deserves an equal chance, but it happens that the Asian culture highly values education and family, and instills those values (Jewish culture is similar). It seems to work.
If Latinos and Blacks grow up in a culture that values these things to a lesser degree, they start off with a disadvantage. But giving them a free boost (artificially lowered admission standards via preference or however) doesn't seem right either (matter of opinion, that's my opinion), but more importantly, I don't think it's sustainable.
So what's the answer? I think as usual it's to work on the root cause. Make sure kids aren't disadvantaged by accident of birth. Now, that's a lofty aspiration, and very hard to accomplish. But in the end I think it's the only real and lasting answer.
Side note: I'm an MIT alum, graduated way back in 1970. At the time, MIT was trying to attract Black students who they thought could succeed. One of the administration's ideas was to guarantee a four-year full scholarship to such Black students.
Do you know who opposed that policy? The Black Student Union! The BSU said that help for the first year was a good thing, for the student to get started, but guaranteed help for four years sends the message that the Black student can't make it on his/her own, while other students can. My respect for the BSU was really, really high. They were straight shooters.