Coordinated inauthentic behaviours online are becoming a more serious problem throughout the world. One common type of manipulative behaviour is astroturfing. It happens when an entity artificially creates an impression of widespread support for a product, policy, or concept, when in reality only limited support exists. Online astroturfing is often considered to be just like any other coordinated inauthentic behaviour; with considerable discussion focusing on how it aggravates the spread of fake news and disinformation. This paper shows that astroturfing creates additional problems for social media platforms and the online environment in general. The practice of astroturfing exploits our natural tendency to conform to what the crowd does; and because of the importance of conformity in our decision-making process, the negative consequences brought about by astroturfing can be much more far-reaching and alarming than just the spread of disinformation.