  Hate speech detection refers to the task of detecting hateful content that
aims at denigrating an individual or a group based on their religion, gender,
sexual orientation, or other characteristics. Due to the different policies of
the platforms, different groups of people express hate in different ways.
Furthermore, due to the lack of labeled data in some platforms it becomes
challenging to build hate speech detection models. To this end, we revisit if
we can learn a generalizable hate speech detection model for the cross platform
setting, where we train the model on the data from one (source) platform and
generalize the model across multiple (target) platforms. Existing
generalization models rely on linguistic cues or auxiliary information, making
them biased towards certain tags or certain kinds of words (e.g., abusive
words) on the source platform and thus not applicable to the target platforms.
Inspired by social and psychological theories, we endeavor to explore if there
exist inherent causal cues that can be leveraged to learn generalizable
representations for detecting hate speech across these distribution shifts. To
this end, we propose a causality-guided framework, PEACE, that identifies and
leverages two intrinsic causal cues omnipresent in hateful content: the overall
sentiment and the aggression in the text. We conduct extensive experiments
across multiple platforms (representing the distribution shift) showing if
causal cues can help cross-platform generalization.
