I have a few things to say to that. This is an Australian perspective. You can change government policies, with a change of government or change of heart by the government, but community attitudes are not so easy. For example, prior to 1967, if you were an Aboriginal Australian, you were not counted in the census; you were viewed as national flora and fauna. Australia also had a racist and exclusionary immigration policy. Harold Holt, as Immigration Minister, waived the Dictation Test (a potential immigrant was given a language dictation originally in any European language, but due to some objections by Japan, then in an alliance with Britain and British colonies in Asia, it was amended to any language. So, theoretically, a Chinese applicant could be given a test in Czech!) for the Japanese war brides of Australian ex-servicemen. The test itself was abolished in 1958.
In the USA, African Americans were denied entry to some venues and in Australia, Aboriginal people were not permitted to buy alcohol or enter some venues.
So, you can say to a hotelier "You cannot exclude people from entering on account of their ethnicity," but you cannot have people standing outside the venue saying, "Hey, you can't deny them access," and fine them. I'll give another example. A clean, tidy, well-presented Aboriginal man went to make an appointment to get his hair cut, at a unisex salon. The receptionist told him, "I'm sorry, we don't do men's hair, anymore." He was understanding. But when he came by several hours later, he found a man sitting in a chair and he said to them, "You said you didn't cut men's hair anymore." The owner then came out and said, "Oh, I'm sorry, but my receptionist thought it might be confronting for customers to see a black man sitting in the chair." Okay, the receptionist didn't racially abuse the man, but, she did make a racist decision.
So, do previous policies still have an impact today? Yes, they do. And it's not because people can't adjust to changes in policy but because they disagree with them.
If we take the Marriage Equality debate in Australia, the biggest idiot to enter Kirribilli, abbott, made himself the face of the No Campaign. And the No Campaign came out with nonsense such as a baker or cake decorator being forced to compromise their principles. Okay, yes, homosexuality has been decriminalized, and removed from the DSM, and yes, in Australia, same-sex couples have legal de facto status and equal superannuation rights in the event of one dying. BUT, I'd like to give an example of something else. My father knew a man who applied for a position in a company, and he had the position, but when the interviewer asked him if he had any questions, he said, "Is this company Mitsubishi Magna negotiable?" "What do you mean?" "Well, do I have to have a Magna? Can I have something else, instead?" "No, our fleet is comprised of Magna cars." He declined the position. That was not defending his principles. A cake decorator who is asked to make a cake for a same-sex couple's wedding is not compromising their principles by doing so, they are doing a business transaction. The couple wants a cake, so you make it, you decorate it and they pay you for it. The same as the man with the Magna. He wasn't told, "If you come to this company, you must buy a Magna," the Magna was part of his salary package and the company paid for the fuel, the servicing and the registration and insurance and it didn't cost him a damn thing.
When you talk about previously oppressed people, I say, if you could have, previously, gone into a pub and bought a beer, but someone else couldn't, but now, they can and you don't like it, well too bad.
Affirmative action is not, despite what conservatives say, reverse discrimination; it's giving people who would have been overlooked the same chance and considering them on merit.