This is not like Sarah Palin's family going uninvited to an extended families' birthday party, and attacking the guests. That was weird. This is extremely extended family making a political attack.
Tim Walz's sister looked at the picture, and said she knew the entire family, and these people were not part of it. She was wrong, in that there are extremely distant cousins that she does not know.
According to these people, in the mid 1800's Tim Walz's great grandfather had a child, and then nearly 25 years later, had another child by another wife (the first wife having died). Some of these people are descendants of the first half brother, Francis Walz. They do not know the name of Tim Walz's grandfather, but they believe he was a half brother of Francis Walz. The two never lived within a hundred miles of each other, and assumably did not have much contact.
I say "some of these people", because some are relatives of Francis Walz through marriage, some through step parents, and at least one through "unofficial adoption."
John Kerry and George W Bush were relatives too. They were both descendant from Edmund Reade from Essex, England, who lived from 1563-1623. Again, there were different wives.