This is exactly as bad as it looks. There is a difference between possessing information, and using that information to do harm to others.
For instance, if I play a video game that teaches me how to use various weapons, and skills for killing others, I am in fact 'training' to use those weapons and tactics.
Having recipes, notes, price-lists, anonymous letters is no different. You can argue that either is in some way preparation for committing crimes.
Yes, I agree it is scary to think that someone else might be 'thinking' of committing a crime, however stepping over the bounds and making 'thinking' about a crime the same as committing a crime makes us ALL guilty, depending on the imagination of the court.
This is super-dangerous because then laws are no longer 'objective', but become more about how creative the prosecution is, and IF they want to go after you or not.