It's easy to find examples of homemade guns. Here's a blog full of them: https://www.thefirearmblog.com/blog/author/improguns/
Most of them are made with crude metalworking, not 3D printing. Making a quality firearm is difficult; making one that goes bang most times the trigger is pulled is not.
Creeps want that. Anyone who wants to watch nonconsensual pornography is a creep. Much as rape is often about power more than sexual desire, I suspect many of these creeps want to see a politician they dislike in a degrading situation.