It's been made up to be this giant issue in our society, primarily western culture, that somehow white heterosexual middle-aged men have some sort of societal privilege that makes them have a much easier life in general compared to minority groups or other groups that do not fit this bill.
I see it basically as an expression of prejudice against people who are perceived to be in the mainstream by those who, for various reasons - age, education, ethnicity, sexual orientation, see themselves as being on the fringe.
Like most prejudices, it paints with a very broad brush, and feeds into the common human desire to pull oneself up by pulling someone else down.
If you are heterosexual you are in the vast majority and swimming with the current, thus the mainstream. But because it is the vast majority there is no perceptible advantage when comparing your prospects with those of most of the people you will deal with in your lifetime.
If you are not heterosexual you are disadvantaged, but it isn't anyone's fault. You are what you are, deal with it. No one owes you anything.
If being middle aged is an advantage, it isn't the age itself but rather the number of years you've spent in the work force fighting to better your position in life that is the advantage. By middle age you should have earned some privilege, however not everyone has, and the privilege is measured in degrees with a lot more people at the bottom of the scale than the top.
Is being white an advantage? Probably. People are tribal, and more accepting of other people they believe to be like themselves. My skin is white, I wont apologize for it. It's the only skin I've got, I was born with it. I'm fortunate my parents chose to immigrate to a country where my skin color is in the majority. Even so, they faced prejudice when they arrived here from Scotland. My mother tells me they they were referred (sneered) to as DPs (displaced people) by native born Canadians, and it was meant in a derogatory way. But prejudice is everywhere. One of the reasons my parents were happy to leave Scotland behind was to escape the religious prejudice. My mother's family being Roman Catholic and my father's being Scottish Presbyterian, well... from what I'm told the hatred in those years was extreme.
The advantage of being male? I'm not sure about that. Politically and financially it is easy to say that men hold the power, and yet I as a white heterosexual middle aged male have no political power and limited financial resources. I think it is safe to say that most men in this world have no political or financial power. On the other hand, in interpersonal relationships, the power that a woman holds is at least equal to the power that men have, and perhaps the power balance in those relationships is the most meaningful indicator of true power.
Bottom line, when I hear or read the phrase "white male privilege" it goes in one ear and out the other. We are all born with varying degrees of advantage and disadvantage, and it is up to each of us to make the most with what we have, though most of us will fail to do that.
Those who, for whatever reason do well in life, will be resented by those who don't for whatever reason do well in life.
I have a theory that the human race first invented language for the purpose of complaining. Complaining about many things, the weather, food, the smell, but mostly complaining about other people.