Jeff Edited to add: perhaps this is a difference in how words are used on our respective sides of the pond. All the more reason to make sure you're using the words you want to be using
I've noticed him use that word before too and it has the same meaning in the UK: Churning = turning out a lot of rubbish.
I think it's to do with him hearing other You Tuber's use the phrase. Bit of a Freudian slip and sounds as if making maximum profit is the goal, rather than reasoned responses to watchtower.