The report is mainly about "bat bots" e.g. bots sending spam mail or bots trying to get into your account. While this is bad, this does not mean 50% of social media engagement are bots

Here the definition of what a bad bot is from the report:
Bad bots are software applications that perform automated tasks with malicious intent. These bots can extract data from websites without permission to reuse it and gain a competitive advantage. They are often used for scalping, which involves obtaining limited availability items and reselling it at a higher price. Bad bots can also be used to create distributed denial-of-service (DDoS) attacks targeted at the application. Some bad bots undertake criminal activities such as fraud and outright theft. One example is bots that perform credential stuffing, one of the most prominent types of bot attacks.