The American production code, instituted in 1934, dealt with lots of things besides sex in motion pictures. It didn't allow men of the cloth to be portrayed negatively, nor business men to appear greedy, nor did it allow the glorification of armed rebellion. So, besides prudishness, there must have been more than just a little fear during this stage of the Great Depression that the starving American people might start another revolution.
"Mutiny on the Bounty" did not really paint the idea of rebellion in a positive light, but it did paint British naval justice in a rather harsh light. Men who didn't rebel and returned to England were tried for treason and the actual mutineers sailed away to Pitcairn Island, never to face any judicial repercussions for their acts.
Too late to make a long story short, maybe that is why this interesting and informative little short about Pitcairn Island in 1935 gets so preachy - to make up for the rather libertine message of MOTB. It talks about how the inhabitants of Pitcairn Island are all descendants of the mutineers and their islander wives. Thus you have things like one interesting wedding announcement that says "Mr. X Christian will be married to Miss Y Christian on Saturday. Let anybody who has reason why these two should not be wed report to the registry office." It shows one girl getting water from a well and mentions that the vase she is using is actually from the Bounty itself.
Then it oddly starts going into the ill effects that all of the inbreeding has had on the descendents of the mutineers and somehow tries to make this the "sins of the fathers", talking about "their evil deed" of mutiny. Funny how no mention is made of the cruelty of Captain Bligh who brought on their rebellion.
Finally it mentions how Mr. Christian, leader of the mutineers spent his final years sullen, alone, and unhappy. Hey, with half of the islanders seemingly named "Christian" he couldn't have been THAT unhappy or alone! I'd recommend this short. Just try to ignore the preaching and pay attention to the actual facts revealed.