In 2006 Major League Soccer commissioner Don Garber famously said "We don't want the local bail-bonds company on the front of the Columbus Crew jersey." Were multi-level marketing companies like Amway, who just signed on as the shirt sponsor of the San Jose Earthquakes truly what he had in mind that day?
Sure, the FTC officially ruled that Amway isn't a pyramid scheme, and nobody has been able to prove that they constitute a cult. But do you really want your team/league associated with a company that's had to defend itself from such allegations, as well as lawsuits from a number of governments?
You might note that MLS is not the first American sports league to be associated with Amway. Co-founder Richard DeVos owns the Orlando Magic. Is this good or bad? I'll leave that to you to decide.