It is certainly discrimination. Evidence has been collected and judgements made, e.g. that African-Americans are severely discriminated against, and special provision be made for them to compensate.
This is specifically trying to be fair, rather than trying to make access equally difficult. I don't know why that is hard to grasp. I don't think 'righting injustice' is bad way to explain it.
Harvard is also discriminating against Asians because there are 'too many'. This seems quite likely but is a separate issue. The historical injustice is present, but cannot be said to have the same character. I don't think criticism of other minority AA programs is justified, but you can have your own opinion.
