Am I the only person who cheers the mistreatment of irritating idiots like this guy?

Dear Prudie,
During one of my aimless walks around the neighborhood, I came upon a sign that read, "It's a Girl!!" posted in the front yard of a house. It was a large store-bought sign, complete with images of storks, pacifiers, and a birth date of four days earlier. Thinking that the new parents would be in the mood for some unsolicited congrats, I knocked on the front door and announced, "Congratulations! What's her name?" The response I got was hardly what I expected. A man, who I'm assuming was the father, answered the door, looked at me with a hostile expression, and said, "Excuse me, do I know you?" Then he slammed the door in my face. Now I understand that it's generally bad form to go knocking on strangers' doors, but when you place such a billboard in your yard, shouldn't you at least be polite? Was I the one out of line? I should also add that I'm a 33-year-old guy with no kids of my own.

—Annoyed