Very often universities find it difficult to attract good Java/C++ teachers in classes. If it is difficult with C++/Java people, it might be even more difficult with Perl people. Here's a comment on both teachers and students of a course at my university:

Teachers. We have a course on Perl at our Informatics faculty. The course mentor is a mature professor from Formal Systems. However, the teacher assigned is a PhD student - he amazingly contributes to many open source things. If not him, we'd have no Perl course.

Students. Of the ~15 students that follow this course each year ~3 really understand what's going on there. And usually they end up really involved in the course. Others follow the course just for passing. As of me, I think it was an excellent course taught by an excellent guy.