One would think that you'd like to get the media on your side, but targeting them would be a bizarre way to do that. However, the media seems to be helping them with as much zeal as if they'd gone after tobacco or gun companies, or the RNC...

The reason the media is targeted is to enhance the effect. Those behind the anthrax are either incapable of getting a better bioweapon or -- God forbid -- are holding more effective weapons back. The only way in which anthrax is an effective weapon is to cause fear -- yes, it's highly unlikely that _you_ will catch anthrax this way, but how many people will want to take the chance?

Attacking the media ensures the word will get out, and that the news will be laced with fear. For example, Sam Donaldson was asking Thompson stupid questions because Donaldson's wetting his pants in fear of being a target. This enhances the effect of a very weak weapon.