The blog has been taken down, and I don't have a copy of the whole post, so I can't judge whether it's reasonable to prosecute him for threatening or inciting to violence or conspiracy, all of which are IMO perfectly reasonable for a society to consider crimes of speech. And I also know, because TJIC is a friend of mine, that some of his weaponry is beyond what I feel requires constitutional protection.
But the episode makes me profoundly uncomfortable anyway, because there aren't any charges. I don't like that cops can just take anything they feel like, handwave that there might be a trial about it someday, and then you never see your stuff again. I don't know if TJIC should get his guns back or not, but I do know that a jury should decide that, not a police chief.