You'll love this Gary Halbert Newsletter - it's the best critique of all that is wrong with Multi Level Marketing I've ever read. It's worth reading right to the end - it makes John Oliver's take on MLMs look tame in comparison.
www.thegaryhalbertletter.com/newsletters/zdla_multi_level_marketing.htm
For those of you who don't know, Gary Halbert was a wordsmith who specialised in awesome sales letters. He thought MLM schemes were "always stupid" and was sick of being approached by network marketers hoping to cash in on his marketing expertise. He threw some network marketers out of a seminar once. He even warned his staff that they would be fired for simply giving him a message from someone enquiring about MLM schemes.
He didn't mince his words, or suffer fools gladly. Here's one of the more palatable things he wrote about MLMs:
... Everything about MLM is bad. MLM is not inherently evil but it does (nearly always) attract inherently evil people. Even if you start out with good products, good intentions and good people, you will eventually, if you grow a little, attract a massive amount of human scum into your operation. And, even if this were not true, the whole idea is still stupid. When you shuck right down to the cob, MLM is simply a magnet for lazy people who are looking for a way to sell without selling. The whole thing sucks.
Like I said, it's worth reading the whole letter from the beginning to the end. It's a cracking read. 