I'm going to collect these kinds of tweets and use them to write a book on how not to argue. When all you've got is the tired "White Privilege!" line -- which should be considered an internet-era argumentative fallacy it's so impossible to defend against and therefore such a shameless line of attack -- you've pretty much already lost the fight.
You wanna discuss issues like reasonable people who for the most part have respect for each other's views, perfect. You wanna make the pious and asinine claim that somebody's not allowed to comment on something in a way you disagree with because he or she happens to be of a certain race, sex or ethnic background, you're not even worth listening to.
Incidentally, this whole Onion thing isn't about race and never was. I consequently didn't inject race into it, but it's fascinating the number of people who are happy to.