OSS people tend to think that a specific license is a technicality only needed because it is legally difficult to put things into the "public domain," and that OSS is actually something that has to do with the "spirits" and "souls" of pieces of software, their developers, and their users. The "spirit" of OSS is violated by anything that doesn't seem "fair."

Free Software people think that Free Software is a set of software licenses designed to support certain social outcomes (i.e. they think realistically.)