I'm no academic, but it seems wrong to me that any field would require the use of a particular proprietary software in order to do one's homework assignments.

May Excel or SPSS be the best tool for the job? In many cases, sure! But students should be allowed to use whatever other software can also get the job done, as long as the software exports the assignment in a data format that the professor can reasonably ingest (e.g.: turning in a CSV file, which can be understood by many different kinds of software, not just Excel).

I understand professors have limited time to check homework and thus don't want to spend time learning how to do anything but open a single, specific filetype, but that's besides the point.