Not a troll but a paid review mill worker who posted on the wrong page. (annerallen.com)
There are paid review mills out there who, using one or two credit / debit cards, can post hundreds of reviews under different names, thus pushing up an author's chances of having his or her book bought. (patrickdevalera.com)
(I've personally seen review mill sites, but they move around, so I don't have a link right now.) (annerallen.com)