The extreme left has plenty of absurd notions and ideas, obviously. Thing is, they don't usually get their crazy ideas put into law. And, as in this case, I think this is whole milk sentiment is representing a far smaller portion of "the left" than OP is certainly in this case. Sharing blogs on issues you find detestable is just a waste of time, on the left or the right. Come running to me when someone is proposing a bill to ban milk because it is racist and I will certainly be on the side of milk. Or, if you want to be more realistic, come to me when the Washington Times publishes their own actual article about how milk is racist and I will denounce them with you. This is not that. This is an opinion piece by no one that matters.
Just to be clear, I do find the whole premise of this college student's opinion on milk stupid. I have known plenty of college students who have stupid as hell ideas. To conflate this person's view as being representative of the left in any meaningful way is dishonest. A person having a stupid opinion is nothing of significance, you have to show social impact (laws, economic consequences, extreme politicians, etc.) to demonstrate an opinion has become a problem.