I still feel bad about the inch of paint or so that I dinged up on the left wingtip of the 182.
My co-owners have always been exceedingly gracious about it. They even pointed out the well-camouflaged twin scrape that had been touched up on the right wingtip that I had ever noticed.
I was mortified and still am to some extent. It's in my head, not theirs.
In Ken's case, he handed the airplane off to professionals, and they did it. The owner could have easily done the same thing unless he supervises all aircraft movements personally. As an owner who's watched line guys drive off with my 182 hooked to a tow bar and a pickup truck, I can say its unlikely that you can always do that.
If the owner is blaming Ken for it after everyone else on the planet agreed it wasn't Ken's fault, there's something wrong there, but not with Ken.
If the owner isn't blaming you and isn't looking at you funny, Ken... It might be in *your* head.
Maybe the owner hasn't made the logical leap to "Would I have done anything different than Ken did?" or, "Who really damaged the airplane here and caused me this headache?"
I'd just ask him if he's still bothered by your decision to hand the keys to the line guys, Ken. If there is something he thinks you could have done differently, he'll say it. Ask in exactly those terms.
He either has to say yes, you shouldn't have handed over the keys, which is unreasonable IMHO, or he has to transfer his frustration back where it belongs.
That said, he may always associate you with pain and suffering caused by having to arrange a repair. But at least he might get over overtly blaming you for it.