I'd have to know more about the schedule of classes to make the statement it's definitely unfriendly. For a dept with evening classes, I don't think it's unfriendly (or iffy.) For a class that meets in late afternoon/early evening, not weird. For athletes who have afternoon practices from 2-5, a TA with evening hours is not unfriendly.
JMO
The class in question was an undergraduate, freshman level class that met and still meets in the morning.
Night time office hours are almost unheard of.
Many reasons. Even full professors can't get away with it, in terms of the evaluation process. Of course, there's nothing to do to a full professor who does something this weird, but basically, it is easily perceived by deans and department chairs as an effort to decrease student interaction/traffic to the office hour. Office hours are supposed to be scheduled at convenient times (preferably just at that point in the daytime schedule where most regular lecture classes end - about 1 in the afternoon, many places).
It also affects student safety.
Putting one's office hours at night or on Saturdays or late on a Friday are all regarded within academia as standard but foolish attempts by (lazy? avoidant?) teachers to avoid student interaction (which is part of the job).
Where I work, that person would not be invited back on that basis alone. Since BK had altercations with the First Year Mentor (Snyder), perhaps it was over this issue - as Snyder would certainly have been required to let the guy know this was NOT okay. During the entire tenure process (at every college/university that I've worked), office hours are expected to be set at optimal times for students. 6 am is frowned upon as well. 8 am is barely acceptable (I have done it - one time a week - out of 4 office hours; I did it as the department chair and senior member of the department - because faculty avail themselves of others' office hours as well). No students came by.
At a time when women are being offered escorts, free rides and so on (at university expense) in order to meet accreditation standards for safety on campus, we are all given notice at many levels that night time classes should likely end earlier, and that provisions be in place for non-night time offerings of the same material (hence the popularity of online courses),
I should add that men can get escorts too. Where I work, both sexes have their choice of a man or woman to accompany them (and I just learned that by far, women would prefer a man to accompany if they are frightened enough to contact the service in the first place). That was the role of the guy who walked KG and MM from the food truck. Where I work, almost no men ask for the service. But then again, there have been no rapes of men on our campus (ever, that I know of) and no recent assaults either.
IME. IMO.
And I do believe that it's possible that any or all of his fellow grad students suspected him of the murders right away. Suspicions come in waves and in varieties. I'd be very, very surprised if no one in a criminology program (including the faculty) would not have at least considered it, given the altercations and the misogyny. In fact, I harbor a theory that Prof Snyder himself likely contacted WSU police (or U of I police) regarding the murders and may have mentioned Kohberger. This would explain the State's keen desire to keep all witnesses secret, to have them in front of a GJ, to be reluctant to give Kohberger that list of people until trial. If for any reason, this man is let out of jail, no one wants to have these witnesses known to him.
I'd bet good money that at least 1 person (outside of police) at WSU did in fact suspect him and further, that they mentioned it to someone else.
IMO.