The key word is "allows"...not "requires"...i.e., the word "may" in their policy. There is also the possibility that they have doubts about the relationship. The fact that you said it took them 4 years to adjudicate your case implies (to me) there is something else going on. Did you have RFEs? Unfortunately, I don't think denial is the decision of just one officer. I'm sure there is a review process. Good luck.
As I said before, your case is a real money maker for an attorney.