After some thought, I think I know why it comes up so often in this context. It's a unique meeting of three conditions:
- "Loser," while it seems like a simple enough word to me, has an unintuitive spelling in the sense that a single "o" makes the "oo" sound.
- People in written conversations don't use the word all that frequently. Amway people use it a lot because of the nature of the motivational material and how they're taught to regard those who criticize the group.
- Not to overgeneralize or anything, but it seems like a lot of them are pretty dumb.