I understand your point but to be fair the players Rex has drafted on defense have turned into really good players. Wilkerson is a star and Sheldon is well on his way to becoming one as well. Coples was really good last year, then got hurt this year in the midst of a position change. He got off to slow start but has been playing really well recently and looks to be back in form.
Wilson has been a disappointment and Milliner is still learning but all in all those picks have really worked out. Not to mention another young player who has become one of the best nose tackles in football in Damon Harrison.
If anything i'd say that the offensive players the Jets have drafted early have not panned out. The front office and Rex have definitely neglected offense for defense though, it least when it comes to the draft.