Yeah, this dislike of Jo as a middle name makes me sad, probably only because it's also my middle name, after my grandpa. It's also my niece's middle name, but after her paternal grandma.
To be honest, when I was a kid I wished it would have been Josephine because I thought that's a prettier name and because I thought people would think it was backwoods or hillbilly. It's disheartening to see I wasn't exactly wrong.
As an adult I like my name because it's mine. I'm not Josephine, I'm Jo, and I'm not upset about it.