Sports writers and commentators, like everyone else, engage in herd mentality thinking. (There are exceptions, such as Skip Bayless, but his 'contrarian' approach is so rehearsed and so transparent, and he's such a douche about it, and his contrary opinions so often either border on or cross over into absurd, that I don't count him.) Once someone has a label slapped on him/her, reagardless of how well earned, the sports press cling doggedly and (as a rule) uncritically to the label. My guess is that a good share of them who spout unequivocably that Draymond or Leonard are defensive player of the year have no real idea of the underlying statistics supporting their case, or even what the criteria are or should be. They just hear everyone else say it, so they repeat it. It's self-perpetuating.
But it cuts both ways. Once Gobert finally crosses the threshold and officially gets the mantel laid on him, then he'll benefit from the same herd mentality moving forward.