They really are making this argument.
If you paid even a cursory amount of attention to the conventions then you'd know that the RNC's Monday schedule was tabled due to Hurricane Gustav. The networks were covering a natural disaster hitting the Gulf states.
The media was covering a 4 day RNC convention with 3 days of actual footage. The media covered all four days, uninterrupted by that partisan Mother Nature, of the DNC convention.
Perhaps the media was trying to, oh, you know, squeeze and extra day of coverage into the remaining three days.