Peggy McIntosh is a feminist, clearly speaking to white feminists. So, again, she is not necessarily speaking to you all. Her choice of audience may make some of you feel alienated. It's important to remember that for many (not all) white males of middle-upper class, that it is hard to identify with these experiences unless they’ve experienced some kind of issue that they can tap into to understand how it feels to be voice-less, or to be taken advantage of. Sometimes you have to reach back into that place to understand. For many white men and women, white people in general, this is difficult to talk about. Women, though, tend to be able to identify with these concepts on some level because they have experienced a level of gender oppression. This is not to say that it's easier for them to understand, but they can at least refer quickly to their experiences of gender difference for comparison. They probably have examples that come to mind easily, whereas for many men it takes a bit more searching. Feminism and gender differences are much more acceptable to talk about in this society–and men tend to be able to accept some of this talk (respect women, equality in the workplace, etc) more readily and comfortably because they see women as partners. On the other hand, when it comes to race, ethnicity, and sexuality, everyone becomes uncomfortable. Our society pays a lot of lip-service to equal rights, but it is a sad truth that our country has not had equal rights for many years. We have to acknowledge the scars of a racially-charged history. The easiest, most common, and perhaps most powerful examples of racially-based oppression in America are the takeover of Native American lands and the enslavement of millions of Africans. It's not comfortable to talk about these ugly practices, or the ugly consequences of them. Like it or not, our country's history shapes our social ideology. It takes a lot of work and ideological brainwashing to justify the takeover and enslavement of millions of people, just as it takes a lot of work to undo all of that.
But more importantly, and more difficult, is understanding how/why/ and when you are a culprit of oppression. This is not necessarily a fault of yours (true, you or I may have engaged in racist/sexist/etc speech or actions, which we could be blamed for), but it mostly is a cultural fact, and it is a system we all participate in. Additionally, even those who have experienced some kind of systematic oppression (for example, language suppression) might advocate for our own assimilation or oppression into the culture because we want to conform and erase our difference so badly. It is important to resist the urge to just deny our complicity in a system where we earn various privileges others do not. It's not easy to digest; nobody likes being told that we are wrong. But if we are wrong and nobody tells us, then we will continue to perpetuate something horrible without knowing it.
So when we talk about these things, those of us who are granted more power within society get defensive and uncomfortable, understandably so. But guilt and defensiveness end up being unproductive emotions. What we have to do is to ask ourselves, what is our level of responsibility in this? In what ways are we responsible for contributing to, challenging, or perpetuating the current systems of power and inequality in the USA? What choices will we make to act upon our responsibilities as citizens in the US? What definition and shape will we give to our citizenship, knowing that we have "more" citizenship rights than many others, or that we are considered "full" citizens while others tend to enjoy a muted or limited citizenship? What control DO we have over the systems at work around us?