Christian was an asshole who gaslighted her and was clearly going to cheat on her even if when he did it he wasn't really in control. He also steals Josh's idea for his thesis.
Josh knew what an attestupa was (based on his reaction when Pelle tells his what will happen tomorrow) yet did nothing to warn her about the details. Knowing what she just went through, this also makes him an asshole.
Mark is ironically the one who is the least mean to her, just kinda ignores her, but constantly insults and disrespects the people of the commune even before things start getting weird.
Pelle is of course leading most of them to their deaths (like, yes they're assholes, but none of them deserve THIS), and takes advantage of Dani's fragile state.
Simon and Connie are the only two who seem like relatively decent people, but they're not focused on much and are removed much earlier than the others.