I assume things like:
a) Alleged sexual assault of staffers (which again, alleged, but could be considered evil)
b) Leaking of personal information that is of no public interest, e.g. unredacted SSNs
c) Leaking private medical records of otherwise ordinary individuals, including e.g. medical records of teenagers who were raped
d) Leaking the names of people who are LGBTQ+ in dictatorial countries where that's illegal, putting their lives in danger
e) Timing the release of DNC hack is arguable, but I could see how someone might consider the timing of that release to be evil
f) There's some antisemitic stuff happening with Assange/Wikileaks. There's nothing like, glaringly out of line, but there's a whooole lot of stuff that's just over the line. (e.g. use of (((name))), calling his opponents "Jewish" media, employing holocaust denier and denying it, etc)
g) Assange himself is quoted as saying, "[We might] have blood on our hands" due to their editorial policy of publishing everything, unredacted, about potentially vulnerable people