I don't think you can delete the news channel, it's built in. You can move it to the very back of your channels list by dragging it with A+B.
I'm pretty sure you should be able to delete everybody votes. Go to Wii > Data Management > Channels.
You probably went to Wii > Data Management > Save Data.
I haven't deleted anything yet so I'm not positive but it seems to me that this would be how.