Sounds like you're lucky he turned and didn't t-bone you as you turned in front of him.
I do think this is a fair point. My position is still the same that, but for his illegal U-Turn, the accident wouldn't have happened and that the road is designed to accommodate both turns at the same time. That's why Trekker is less at fault.
On the other hand, if he didn't have his signal on, he could have been going straight. Had he gone straight, there's no question that Trekker would have been 100% at fault.