In any sort of business, there is always a contract or agreement: you agree to do this, in exchange, I agree to do that. In a job, you agree to work for me, I agree to pay you. It is no different in a MLM.
If there is contract, just "recruit!" then it's obviously a pyramid scheme.
But even if there is a contract, there are hidden clauses with which the company can just discard you like rag doll after it no longer needs you.
Here are some such hidden time bombs hidden in "independent distributor agreements".