I still hear this on occasion:
Free/Open Source software is a nice idea but students need to be taught Microsoft products. If you don’t, you won’t be preparing them for the real world.
Typically, Microsoft software is proprietary so learning the inner workings of such software is verboten unless you sign an agreement not to share and cooperate with others (which is antithetical to my philosophy of education). With proprietary programs, students are forced to act only as users of software if they wish not to agree to break a social bond of goodwill. Schools that adopt free software not only teach platform/application-independent, transferable user skill sets through conceptual understanding, but also offer the opportunity for students to explore programming through the very software their institution implements and peers use. And it just so happens that the “real world” is more than ready to embrace them.