Re-reading this thread, can I suggest that the anti-reiki lot are just a little bit forthright and robust in their posting style, rather than outright rude?
Anyway, I spotted this query by Cote which hasn't had an answer yet:
Why threefold and not twofold or fourfold? I'm curious.
Because three really is a magic number. For some reason the human brain loves the number three. Sorry, I can't find any links right now but there have been studies carried out which demonstrate that humans will be drawn to the number 3, which is why it's used quite a lot as a marketing ploy - we will be drawn to a "3 for 2" offer above a "2 for 1" even though the latter is a better bargain. It's also something that speechwriters use to provide emphasis, e.g. "Education, Education, Education", "Vidi, vici, veni"
and so on.
Anyway, this love of the number "three" led to the development of something being returned threefold during some neo-pagan rituals, and eventually to the development in 1960s/1970s Wicca of something called "the threefold rule", whereby what you give out, good or bad, is returned to you threefold. Quite obviously this doesn't bear out mathematically or in reality, but does provide a very basic ethical framework to live by, i.e. "think about how you behave and treat people and act as if everything you do will be returned to you threefold". Wicca has been a strong influence on most neo-pagan paths and so this tenet has become popularised by those who are interested in neo-pagan spirituality.
I hope that answers the question.