The last bit may be. The former, probably not, until a court orders them to hand it over.
Just think about it in the context of a person doing this. If you witness a crime, you don't have to hand over, for example, video of the crime just because they ask for it. They need to get a court to order you to hand it over. Or, if you commit a crime, you don't have to provide them with evidence. They have to have a court order you to hand it over.
Again, if they actually cared about law enforcement then they'd obviously hand it over. They don't though. It's just not a crime that they aren't handing it over until they're ordered to. It proves that they are the enemy, and not legitimate law enforcement, but that isn't illegal.
The issue with a "no politics" rule though is that everything is political. It ends up just being the mods removing what they want to remove and letting what they want to see stay.