We Americans like red hair. In general, it's beautiful.
I was shocked by an article which appeared in the Kansas City Star not too long ago, reporting that in Europe (or maybe just British Isles) people with red hair are disliked. One such person told of being spat on on the street for having red hair. (They call it ginger.)
Another man said he had left England for America and was very glad not to deal with prejudice red hair.
It is common to imply that redheads are bad-tempered or promiscuous.
My grandmother, who was born in 1888, told me of something similar. She was taunted and disliked by the other kids in her Indiana town. Then one day, a woman she had never seen before stopped her on the street and told her she should be glad for her red hair. It was beautiful and few people had it. That changed Grandma's whole attitude.
These attitudes don't seem to be explicit in 'The Tinkerman's Daughter,' but neither do I think it's 100% an accident that the faithless wife is redheaded.