I am betting this guy is dead on in accurately describing how "check your privilege" is actually used by 99% of the people who say it. It is just the kind of empty headed platitude that people with zero rational argument would resort to in order to blindly dismiss arguments they are intellectually incapable of responding to.
If there is an actual fact the person is overlooking, then you simply point to that fact and explain how it is relevant. When you are incapable of pointing to any actual facts or flaws with a person's argument, then you use their skin color or gender to assume that they must be overlooking important facts due to "privilege", even though you yourself don't know what these "facts" actually are.
Not to mention, he is at Princeton. Most of the minority and female students there also come from relative privilege in the dimension that determines privilege far more than race and gender, wealth.
do you have any proof that 99% of the people who have said check your privilege to this young man mean exactly what this this says they do?
No, you don't.
Which why I asked what it does mean. Although doubtless meant well by those who use it, it doesn't seem to be me to be advice you can actually act upon.