Review bomb
A review bomb is an Internet phenomenon in which large groups of people leave negative user reviews online for a published work, most commonly a video game or a theatrical film, in an attempt to harm the sales and/or popularity of a product, particularly to draw attention to an issue with the product or its vendor. While a review bomb may be a result of consumers criticizing the poor quality of the product, it is more commonly associated with perceived political and cultural issues around the product, its vendor, or related works. This is often done to draw wider and mainstream attention to to that issue, especially if the vendor does not have an open communications channel or seems unresponsive to direct feedback, but may also as a means of mass-driven coercion or simply a result of trolling. Review bombing is a similar practice to and shares characteristics of vote brigading.
Read article on Wikipedia