Who are Mass followers in the Audience Type section?

Instagram users with more than 1500 followings are identified as Mass Followers. In most cases, Mass Followers take an advantage of using automatic following and unfollowing services. They try to grow their followers' count in such an inauthentic and quite ineffective manner by following tonnes of irrelevant accounts hoping them to follow back.

However, according to Instagram algorithm, you are not able to see Mass Followers' posts in the feed updates.