Here is the chain of reasoning:
We are the only true religion.
How can we prove that?
We take the "food at the proper time" from house to house and door to door.
No other religion can say that.
What you take to the door is just crap. Why would the True Religion take crap door to door?
The light grows brighter and brighter until....blah blah blah. We NOW know more than we did before.
If something is True you can't change it. If something is false you can correct it. If you say something is True when it is false you are a liar and have to change it when you get caught!
Apologia: What other religion has all the True teachings on Hell, the Trinity, Armageddon? Where would we go if we leave Jehovah?
Refutation: A clear glass full of thirst quenching milk with a drop of cyanide in it: why wouldn't we go ahead and drink it???
A little leaven ferments THE WHOLE lump.