The problem with this seemingly high-minded ideal is that every intervention has a cost, and they add up quickly. When oppression is blatant, violent and extreme it's relatively easy to identify, the benefits of mitigating it are large, and the cost to society is low. But when the 'oppression' is subtle and weak, consisting primarily of personal conversations or even private thoughts of individuals, the reverse is true. You find yourself restricting freedom of speech, religion and association, creating an expanding maze of ever-more-draconian laws governing every aspect of life, throwing out core legal principles like innocent until proven guilty and the right to confront one's accusers - and even then, success is unlikely.

Another important factor is the fact that those who consider themselves victims will never be satisfied, and indeed this whole campaign in their name quickly ceases to improve their lives to any measurable degree. As you noted yourself, individuals tend to rate the trauma of an unpleasant incident relative to their own experiences. So once you stamp out the big, easily measured objective forms of oppression, you find yourself on a treadmill where working harder and harder to suppress the little stuff doesn't do any good. Each generation feels that they're as oppressed as the one before, even if objectively things have changed dramatically in their favor. The only way off the treadmill is for the 'victim' group to stop viewing every experience through the lens of imagined oppression.