Plus, sellers wash their hands of this by paying a company to boost their listings. It's don't ask, don't tell on how they accomplish that.
You buying positive reviews is intended to make more money for yourself by getting as many sales as possible including if it means another seller doesn't get that sale. The person buying negative reviews is intending to take sales from others so they get the sales instead. Either way, the intent in both situations is to increase one's own position at the expense of others in a fraudulent manner. You're both just as guilty.
I don’t understand why you need particulars if fraud is fraud though. They both got difference sentences and did the same underlying crime. Why do we sentence people differently, or is the view that we shouldnt be doing that?
Because there's no real way of measuring the cost of a fake review to Amazon. Yes, Amazon could do a lot more. What's the right amount to do? How much should be spent on that initiative, and why shouldn't that money be spent on other initiatives?
Safety and genuine goods are important things. If they can't or don't care about that, what makes it any more reputable than random vendors on aliexpress, for instance?
Amazon could do a lot more. I've just opened up Telegram to see what's happening in the scam review groups today, and within seconds I can see that this wifi range extender is being boosted by paid-for positive reviews: https://www.amazon.com/Extender-Wodgreat-Wireless-Repeater-I...
(The 5-star reviews on that page confirm the theory).
If I can do that, on a Sunday morning, from my home... why isn't Amazon?