Earlier quoted context omitted.
If cushing is not full, why aren't people buying at $2 a barrel now and storing for one month, selling the June contract at the same time and collecting a $20k profit per contract?
Just a guess, but maybe the consensus is that June is going to be the same (or worse) as May and they are going to have trouble unloading those contracts? It may come to the point that you're paying some to take the contract.
The problem is that you have to store the oil for a month which is pretty expensive right now.