What's the difference between telling a child
a. Armageddon is close, so be a good JW and survive
b. Be a good Christian so that you don't burn forever
c. Worship a pink jellyfish
Answer: Nothing. The beliefs are different, but the proof for all three is non existent. I'll even go as far as to say worshipping the pink jellyfish could be the most benign one there, but I can't see that argument swaying anyone to think it's okay to teach children that.
Strictly speaking, your 3 examples do not refer to the same type of belief. The first 2 do not refer to a belief in a god per se, but in matters pertaining to practice or doctrine.
As for the 3rd one, is there ANYONE around who worships pink jellyfish sincerely? A real god, it occurs to me, doesn't let faith in him die out once he's revealed himself . Why would he? and that makes me think, has the pink jellyfish revealed himself to anyone? So no, the pink jellyfish is not in the same league as the Christian god.
The world, and man, attest that they contain within themselves neither their first principle nor their final end, but rather that they participate in Being itself, which alone is without origin or end. Thus, in different ways, man can come to know that there exists a reality which is the first cause and final end of all things, a reality "that everyone calls God".
So you can call it the Flying Spaghetti Monster or the Invisble Pink Unicorn or whatever cutesy names you can think of to get everyones dander up, but what we are referring to the First Cause and Final End, commonly called God.
Another question: Would any parent of young children here be okay with the idea of their child being taken to learn about Hinduism every week as fact instead of Christianity? If not, why should they be told Christianity is exclusively true because by pure chance they happened to born to Christian parents? Why the double standard?
There is no double standard. We teach our children what we hold to be true. So would any sane parent. We also connect them to the chain of our past and future by delivering the traditions we have received. Your comment reminds me of why my grandfather packed up and left atheist communist Cuba, my father was going to come of age for the atheist brainwashing that boys get at 15. He gave everything up and left the country with his family and they went through much hardship.