A group of haters is commonly called a Horde. Other collective nouns you may see include Gathering and Cluster.
Collective nouns for haters can be described as a vindictive coalition, a spiteful swarm, or a malicious mob. These nouns aptly capture the essence of a group of individuals brought together by their shared animosity towards a person, idea, or concept. Within the realm of haters, these collective nouns illustrate the intensity and number of those who harbor negative feelings, eagerly seeking validation and unity within their vitriolic pursuits. They portray an image of a force mobilized, with an intent to antagonize, disparage, and foster a climate of criticism. The usage of collective nouns taps into the volatile nature of hater groups, emphasizing the potential mass impact they can have on unsuspecting targets.
Known collective nouns for Haters include: