It's because bitcoin is a decentralised currency not owned by any banks or financial institutions.Its true that bitcoin is used for illegal activities.I think that these financial firms are funding media to conduct a propagation against bitcoin as they suffer from bitcoin a lot and just misuse the media for the benefit of their interests.
People use bitcoin for money laundering because it is unidentified onwner they cannot send summoned if ever elligal transactions caught by the law enforcement.