nate isn't a nice person by any long shot. he's a literal asshole, a dickhead and far too aggressive to be considered a soft person. he struggles with his masculinity so that manifests itself as sheer anger, 

he's a misogynistic, abusive pig asshole who would rip shit to fucking shreds just because he felt like it and because he's nate jacobs.

so when he finds you in tears at the party, he assumes the worst and gets fucking angry.