I think the initial assumption comes from emotion. Humans are not dual creatures with frontend and backends that must communicate through an API between their emotions and thoughts. Emotions and thoughts are actually phenomenon in simultaneous occurrence-- your thoughts can trigger emotions (planning what to do after being laid off can trigger anxiety) and your emotions can trigger thoughts (you're anxious, so you consider putting planning off and binge a show/movie).

Fear of the "other" is clearly an emotion, but all the justifications, reasons, and overall narratives about the "other" are thoughts.