I honestly don't understand this lack of pride in one's ancestors.

To me, the reason WHY someone ended up somewhere and then helped build the country is irrelevant. It's what they did later that counts, and some did truly great things.

Unless...they were afraid of contests....

"My granddaddy was sent out for stabbing a constable!"
"Yeah, in the thumb! My grandda was sent out for doin' a horse! Nyah!"
"Well, you two guys ain't nuffing! My dad came because he offed two peelers and took a shot at the bloody Queen!"
"Sure, sure, and my grandma ran a bawdy house frequented by the Prince of Wales!"
"My mom and da came over 'cause he was governor to the prison."
(pause)
"Let's beat the crap outa him!"