Please explain why MLMs are considered so bad. (NO hateful or rude comments)

Everyone in here has seen the MLM business plan. You either scale up by selling on your own, or teach your down line to sell the same amount you do, and duplicate. Now I understand that seeing profits isn’t something that happens right away, but Uber has existed since 2007 and and the didn’t turn a profit until 2022. Does that make the founder a scammer with regard to the investors? Point is, MLM takes work, and recruiting doesn’t get you paid, it’s teaching others how to duplicate yourself that gets you paid, but it also gets the paid, so what’s the real issue? Now I will preface, I know there are many bad people in MLMs that make others feel bad, or falsely advertise the business, but unfortunately, we can’t control how people behave. So the fact is this, is the MLM the bad part, or it it your up line/team that creates a toxic environment? Me personally, I’ve experienced none of the pressure, or extreme losses that are spoken about in this sub, so I’m really tryna understand if everyone’s bad experience has more to do with their environment than the actual business model itself.