I saw your post on the other forum, and I was going to ask you to post it here, but as I see I didn't have to.
As I said, so good to see such dedication and openness on the part of a medical professional. It's not all that typical.
I can affirm what this doctor says, it's my case exactly!
Vasectomies have been practiced for about 45 years, which sounds like a long time, but the kind of damage that is refered to here, takes a very long time, and in many cases, it's not enough to produce problemas with the "barrier". My case was exagerated by a reversal, which more extensovely exposed the urinary tract to anti-body laden sperm. Even so, it took about 10 yrs. for the extended aggression to finally produce POIS.
So docotrs reject the sperm allergy theory because it is very improbable. The blood barrier is quite secure. But remember, POIS is RARE. POIS is RARE. The doctors have to understand that it is NOT a normal circumstance that causes it.
I'm Canadian too, but live in Chile, or I'd try to link up with your doctor to help him perhaps prove or understand this theory better. Tell him though that I am living proof, and thank him for me for being so open to understand and permit potential for movement.