You may just have to "get over" that. I'm pretty sure that they don't care about your student's documents.
However, here's another thought. Don't make it a requirement in the first place. All word processors can export PDF these days. Require that your students only submit PDFs. It won't hurt them.
However, here's another thought. Don't make it a requirement in the first place. All word processors can export PDF these days. Require that your students only submit PDFs. It won't hurt them.