Unfortunately, "Open Source" is easier to market than "Free Software". The real benefits of true free software evidence themselves in the end and that's what counts, not what you call it.
Edit: It is however important to distinguish between free software and thinly veiled proprietary software marketed as Open Source.
What about distinguishing between non-free, but substantially open software (measured by ease of patch submission) vs proprietary software with the occasional code dump?
Edit: It is however important to distinguish between free software and thinly veiled proprietary software marketed as Open Source.