They just follow the course of government institutes. They are told to write bad things about it and everyone follows orders.
You can't just say this kind of things since not all of the articles, videos and blogs are saying bad things to this digital currency. A lot of people especially big names in the trading industry has some good thing to say about this. They might not like other things about bitcoin and some of them created something to mislead a lot of people but if you really want to use bitcoin, it is not that bad since it created a lot of new things out of the world.