Brief response here, since it'd be ridiculous to try to work all of this into a series of tweet-replies:
There are theories out there about how power works which help us to understand what privilege is and how privilege can be overcome. For instance, Marxist theory often examines how various forms of privilege in our society work to the advantage of those who control the means of production by dividing workers against each other. This analysis teaches us something about how privilege can historically emerge: because of Marx, we know that things like racism and sexism are often stoked by wealthy interests, and we know that one way to fight racism and sexism is to wrest control of the means of production away from them. This is not a comprehensive theory of power by any means, but it at least contributes to our understanding of how power and privilege work.
Compare that use of the word "privilege" to statements like this:
Anyone who has seen the way "privilege" gets thrown around in liberal discourse is familiar with this kind of rhetoric. Marxism, of course, is not the only theory of power out there; there are other ways of talking about privilege, how it operates, how different forms of privilege are related to each other, and so on, and some of these are even compatible with liberalism. But it's extraordinarily rare that our liberal media elite actually talks about privilege in this way. When pundits like Joan Walsh and Michael Tomasky use that word, it's not clear to me that they are at all familiar with the intellectual and philosophical framework that gives the word meaning and explanatory value; for them, it's just a cargo cult appropriation of terminology they've seen floating around in a prestige discourse that they want to participate in.
This is all just elaboration on what I was getting at in the tweet. Just because you call an animal a dog, that doesn't imply that you actually have some knowledge of what dogs are - even if you happen to get it right.