Maybe FOSS should stop being like PETA and, instead, tell people why it's *good* to use FOSS. Why Linux is *better* than Windows, GiMP is *better* than Photoshop, OpenOffice is *better* than MS Office. And maybe people will listen. But if you insult their software and tell them to use something else, they won't be very open to the idea.
Too hard, and in some cases impossible. Anyone who has used both 3D Studio Max and Blender will laugh in your face if you try and tell them Blender is an overall better piece of software to use.