I feel your pain. My vets made the comments about the hernia several times when I've been bringing Zoni in for her shots. I just ignore them, wasn't worth the effort to explain how common it is in the breed. But in their favor, they weren't in a hurry about fixing it, waiting until spaying was fine with them.
My vet's office has a general stigma against basenjis. Apparently Nemo is the only basenji in their practice that they are able to get anywhere near(he's a little angel on the exam table :p), so maybe your vet has had bad experiences with them? I keep getting comments from mine to make sure Zoni turns out the same way.
Good luck, I haven't found any vets in my area that are very basenji familiar but I think the best thing is to find one that is willing to listen and learn. Mine was very helpful when I wanted to do the blood draw for the Fanconi test and even looked up info about it before I came to the office. So I see that as a good sign.
I think there are several people in the NE Ohio region on the forum maybe?