That's the fear people have.
Someone will watch GB news to see stuff on some specific topic.And fin them being fairly sensible.
Then they might think - maybe these guys aren't as evil and stupid as I assumed, What else do they have to say?
And then they see a different take on some other topics, and maybe some of it isn't stupid and evil, or it's even convincing, or worst of all, they realize their former sources were really giving a strong slant on the issue.
And all of a sudden they are questioning their political allegiances and maybe thinking about things on their own.