Social media use appears to play a role in radicalizing an increasing number of people. I problematize what I characterize as the current picture of radicalization, where the radicalization of an agent is depicted on a timeline, eventually culminating in an act of extreme violence. I argue that what is particularly concerning about online radicalization is the harm that prolonged social media use and exposure to its engagement algorithms can cause to the epistemic capacity of the agent. I then argue that social media companies are at least partly responsible for online radicalization, since they have created an environment that causes epistemic harm. I conclude by sketching some ways we might combat this environment at the level of the agent and the level of the community, problematizing the virtue ethics-based approach that is common in such recommendations and favouring a legislative approach against social media companies.