Because they've made it so easy and affordable for filmmakers outside of their system to get financing, get distribution, get theatre screens, and get an audience's attention. And if people are successful without their help, it's not long before such people are offered huge sums of money to join them.
The problem is that if everything newsworthy must be paid for, then things which aren't paid for are not reported, or it becomes the exclusive property of the highest bidder, who might simply suppress the footage if they feel it harms them in any way. This makes it an effective form of censorship.
Copyright is supposed benefit the general public, not the copyright holder. Allowing fair use for news commentary benefits the general public, not to mention that copyright law was in no way an incentive to create this particular video.
The community I represent doesn't think much about copyright or fair use at all, which is why you don't hear from us very often. After all, we aren't paid huge sums of money to send you emails like Chris Dodd is. We aren't paid to try and get laws passed and trade agreements made to benefit ourselves. We aren't in the room when all those industry representatives get together to decide what's best for our country. In fact, we aren't even allowed in the room.
But we're the reason you have a job. We're the ones you're supposed to be helping. We're the people most affected by your trade agreements. Your job isn't to help Chris Dodd keep his job, and what's best for Chris Dodd my not be best for us.
All we ask is that you keep us in mind through all of this, because your job, most of all, is to represent us. You're all we've got to protect us from Chris Dodd and all those seeking to profit from your actions. Please stand up for us.