I have strong feelings about this. I think we, as the FOSS community as a whole, should try to be as inclusive as possible. Respecting the freedom of users is a mindset, not a license.
I sell commercial software, with full access to the source. Not Free Software, mind you, but Open Source. This empowers users to tinker and to understand.
I teach students to use Python, in a hitherto very Matlab-focused world (academic audio signal processing). After a short while, the students come to appreciate Python by its own merits, not because of its license.
We should encourage people to use the software we love, because we believe that our software is better suited to understand image processing, which will ultimately lead them to become better artists. But crucially, the goal here is to educate, and art, not stallmannian celibatism.
Furthermore, excluding commercial products from discussion has a high risk of making us blind to developments in the commercial world. There are dozens of companies doing great work in the commercial sphere, with hundreds of programmers immersed in image processing and photo editing. There is much to be learned from these products and people, be they freedom fighters or salesmen. We should strive to learn from them, and gain a broader perspective by including their developments into our world-view instead of ignoring their work in the name of our dogma.
As for my own work, I started out with FOSS image editing software, but have since moved parts of my workflows into commercial products. I will no doubt “come back” in due time, as I have in other areas many times. I am a maintainer of a number of FOSS software, and strongly believe that a FOSS mentality leads to better software eventually. Yet I currently use Windows, and work for a commercial company. It would be a shame if I was to be denied this wonderful community because of that.
And lastly, I don’t know about you, but all my cameras run decidedly un-open firmwares.