I think you might be missing my point.
We don't know why he doesn't want to do oral - I was merely suggesting it might be that he's turned off by the appearance, some might be put off by a smell or hygiene issue - it is probably neither of these issues, but it could be. Or it might be something completely different. We don't know.
And as I stated earlier, there are some things best left unsaid. So let's suppose, just for a moment that it is one of those issues and the guy in question is desperately not wanting to hurt his partners feelings on something that he very well might admit is his own problem, but accepts that it's just they way he is, but acknowledges that he just can't tell the truth for fear of hurting his partner.
In this scenario he might have to lie to save hurting feelings, or just clam up and try to avoid the issue, yet the person doing without might continually keep chasing for an answer. My point is that the truth might not be something that should or cold come out in the open, therefore is there a point when it's best to just leave it?
In answer to your question as to how I'd feel if I was told my partner didn't want to give oral due to the appearance of my penis, I'd have to accept it was just the way they were, but I wouldn't take it personally. Some like anal, some don't. Some like seafood, some don't. Some like beach holidays... etc etc.
My thoughts are that trying to push and push for an answer won't, in my opinion, ultimately result in the OP receiving satisfactory oral, which is the ultimate objective, no?