What type of threat actor engages in actions like defacing websites and launching denial-of-service attacks?

Hacktivists are a specific type of threat actor who are motivated by political, social, or ideological causes, rather than personal gain or financial profit. Their activities often include defacing websites to send messages or promote their beliefs, and they may also engage in denial-of-service attacks to disrupt services and draw attention to their causes. By targeting organizations or websites they oppose, hacktivists seek to raise awareness and provoke a reaction regarding their viewpoints.

The actions of hacktivists stand in contrast to those of competitors, who are typically focused on gaining advantages in the marketplace, or organized crime groups, which prioritize financial gain through illegal activities. Insider threats involve individuals within an organization who misuse their access or knowledge, but they don't typically engage in the public displays of protest characteristic of hacktivism. Thus, the behavior described in the question aligns closely with the motivations and actions associated with hacktivists.