The argument they're making looks like they're saying that Aereo can't stream copyrighted content over the internet, because the copyright owners (the broadcasters) don't want their content used in the manner. This is weird because broadcasters aren't supposed to have copyrights on material once it's been broadcast. That's been Aereo's edge.
Basically they're trying to close the loophole by saying Aereo isn't consuming the signal, hence they are interfering with the broadcast to the real consumer.