It is not clear if there had been prior exchanges with Bruce but Dawson appears to be responding to the refusal of Bruce to follow the appointment procedures for speaking with academic advisers. I can understand that the office was irritated by someone who refused to follow procedures if appointments are required in every academic advising session. If the office had made it clear that it was against policy to see “walk in” students, the refusal to comply and come back with an appointment could be viewed as bizarre. For example, if someone insists on seeing a doctor without an appointment and refuses to leave the waiting room, a nurse could find the conduct to problematic.
However, it is not clear why this became a matter of harassment or possible threatening conduct since there is no sign of Bruce doing anything other than sitting in the lobby. African-Americans often raise concerns (with good cause in some cases) that black males are viewed as inherently threatening by whites in circumstances where the actual conduct is inconsequential or indistinguishable from whites. It is the escalation to the level of harassment and police referral that justifies a closer investigation. Accordingly, I think the university was right to pursue the matter with this investigation.
Bruce also posted an email exchange showing that Dawson and others on the faculty were being unhelpful when he was seeking academic advice. Obviously, there is more to be considered in context of this controversy, which is why an investigation is warranted without assuming anything negative toward either Bruce or Dawson.
