I have a problem/question about a university counselor who seems to be unprofessional to me. I'd like to ask about it on academia stack exchange. Will it be on-topic?
In general, such questions are on-topic, as they clearly relate to academic life. However, you have to consider the following:
The individuals concerned should not be identifiable from your post. See also: Should we name names when talking about bad publishers and researchers?
You should ask a question that you can reasonably expect to be answerable by us without knowing all your details and that may be helpful to others in a similar situation. In particular your post should not just be a rant. See also these Meta posts: