Incivility and hateful language in user comments are met with growing concern among politicians, the general public, and scholars. There are fears that such comments may decrease social cohesion and ultimately result in less prosocial behavior among citizens. We investigate whether hate, or even civil negativity in user comments alone, inhibit actual prosocial behavior through recipients’ explicit and implicit attitudes. In an online experiment, 253 participants read user comments (neutral, civil-negative, hateful) about refugees and received five Euros which they could donate for a refugee aid organization or keep for themselves. The results show that participants confronted with hateful or negative user comments donated less money. The effect was mediated by both explicit and implicit attitudes toward refugees with hate having a stronger influence via implicit attitudes. The results are discussed in light of possible measures for reducing the behavioral impact of negative and hateful user comments.