"But why never some of the other diets? That's what gets to me. "
My theory is that it's because being overweight is a moral issue and people should suffer to lose weight, so if it doesn't involve enough hardship people get weird about it. (Not my opinion on what losing weight shouldn't involve, just what I take from threads like that)
WW is ok because it involves being hungry and tiny portions... SW isn't because god forbid you should lose weight and change what you're eating instead of how much.
I mean the fact that I lost weight with WW while existing completely on 24 points of chocolate a day is clearly not a flaw in WW, but apparently people doing that with muller lights is some sort of marketing plan by SW 