"In other words, third-party sellers aren’t the only ones paying her to leave fake reviews and superficially boost sales — Amazon is too." Would indicate that

"In other words, third-party sellers aren’t the only ones paying her to leave fake reviews and superficially boost sales — Amazon is too." Would indicate that Amazon are and if they are in effect fiscally encouraging this practice then people like Jessica would take that as some form of legalised legitimacy. Which is not the case [edit add] [EDIT ADD] This is just cashback from Amazon credit card, just badly worded in article