That's another of these developers who benefited greatly from FLOSS, yet write condescending posts. Ironically, the author of fman makes use of Qt, which is a great example of how to make a business and still have a copyleft licensed codebase.
My problem isn't with you writing proprietary software, (I'd prefer if it wasn't proprietary, but do you as you wish). My problem is with you people who benefit daily from FLOSS to then act as if the FLOSS people are just crazy hippie, commie lunatics and how you couldn't possibly be FLOSS without also putting food on the table and how other people are apparently not (gosh!) allowed to advocate for not using proprietary software, or how is wrong for them to do so and other such garbage.
I don't care about FLOSS people. Actually, I'm grateful to them and I also have my own set of FLOSS libraries [1], because I feel we as a dev community should work together and not have to reinvent the wheel all the time. What I take issue with is being criticized for writing proprietary software. It happens somewhat regularly. And the silencing that takes place is simply unacceptable.
People are free to say they won't buy your software because it is not free, (as in freedom). Also, there are important differences between merely "open-source" and free software, so am glad to see that fbs is indeed copyleft and applaud you for that. You seem to however be more on the open-source side of things, despite the great choice for a license of fbs.
One thing to understand, is that the free software movement strives for a bit more than open-source. It strives for trustworthy, ethical software. Software that does not spy and only does precisely what the user knows about and can be adopted to work according to one's needs. Copyleft is the best means we have of achieving that.
What I think you're also missing is how hard what we have even now was to win. You're grown up in a world where FLOSS was already a thing and fairly popular, but it is precisely because of the 'fanatics' that it is so and we're still far from an ideal place. If they were so lax as you wish them to be, you may not have all the things you take for granted today, because it is radicals who change the status quo.
You will be asked why fman is proprietary from time to time, because you market to people that have a lot of principled people on this issue in their ranks. You're free to ignore them and they're also free to keep not buying your proprietary product. That's how it works.
P.S. Just to let you know, I did subscribe to fman when it first showed up here and even renewed my license to support a one man shop, despite me not using the tool. Posts like the commie one however, carry with them a serios lack of understanding of the goals and reasons behind the (need for) free software movement.
Nonetheless, as I already said, I applaud you for taking the step to make some of your work copyleft. I am personally strongly of the belief that if fman itself was GPLed, you'd see an uptick it sales, not any downturn, because it would generate excitement and make people like me write plugins for it. At present, I don't want to do that due to it being non free.
As I said, it has a small part mentioning open source, which is still completely irrelevant with its weak argument. I'm not sure what the author is getting at, but it seems they treat open source as gratis, which comes back to the fact that gratis is not the topic here.