Because they (including Francci) know that in addition to the drawings of ancient weapons made by artisans in past dynasties, there is also a kind of people, that is, researchers of historical characters.
Since the O 'Hara incident, Robin is the only one who can read historical texts, and of course, the only one who can awaken ancient weapons except iceberg (or Francci).
So Iceberg kept posting Robin's wanted order in his room to show his vigilance-of course, he wanted to kill Robin because he told Robin that no matter what you wake it up for, as long as you wake up the world, it will be destroyed, so he regarded Robin as a demon.
Francci, on the other hand, once denied the weapon (ship) he made because of the attack on the judicial ship, and was scolded by Uncle Tom, so he thought that Robin's existence did not constitute a crime. It was this sentence that affected Robin's guilt about her existence and made her regain the courage of "I want to live".
It is precisely because of my uncle ... Francci's heroic deeds that I feel that ... he and his sister ... Robin are ... almost ... >>& gt (this sentence can be ignored-).
Uncle Tom built Roger's boat, so the government sent a judicial ship to the capital of seven waters to judge him. So he hoped to make up for his mistake by inventing the sea train.
Spandam forced Uncle Tom to hand over the drawings of ancient weapons, but Uncle Tom flatly refused. Francci had a hobby of making weapons ships since he was a child. By the time the Judicial Ship incident happened, he had built 36 weapons ships with giant cannons.
After Uncle Tom finished the sea train, the judicial ship came. So Spandam attacked the judicial ship with Francci's weapons ship. In order to prevent the iceberg and Francci from being implicated, Uncle Tom took the responsibility of making One Piece. Of course, Francci regretted it. He said it was no longer his boat because it killed his master. At this time, Uncle Tom hit Francci and scolded him severely: The existence of the ship is not a crime, but how to use it is the user's business! A man should face his boat loudly! ! Then he died heroically.