Unless you're an independently wealthy jackass, I'm not sure how you can attack non-FOSS software users. I am a software engineer and I get paid to write software. I write some code for fun at home too and if people use any of my projects Im delighted. But if you want bug fixes and reliability and consistent new features and updates to apis and I have to listen to your bullshit complaints about how XYZ is better, you bet your ass I'm gonna charge for that.
It's like a baker making bread who gives out a few loaves for free at first. You don't get to complain if 100s of people show up demanding free bread and he starts charging them. Maybe communism is a system that demands people work for free, but elsewhere you're entitled to whatever wage the market will bear.
The bread analogy dies at the same point that the piracy argument dies. It isnt truly stealing to make a copy of something.... and it doesnt cost a developer more effort the more people that download their app.
Years ago, I came to the conclusion that the right way to support yourself being a software company was to provide service, not software. I also believe selling software licenses to for-profit companies is a good strategy. Bug bounties are fine too.
Point is, I think there are plenty of ways software developers can make a living without being closed-source or nag-ware. Most companies do not want their employees spending time fixing bugs in software, and many are fine paying reasonable licensing fees as long as their software group is satisfied with the service - which mainly happens when said IT group isn't having to spend too much time messing with it.
You are right, but I see no reason why you couldn't sell Libre software. People never have to pay for software, they choose to do it. It doesn't matter if the app is proprietary or not.
I'm reminded that in the past every release of a software (at least the major ones) would be a single paid-for release. Obviously the google play model inhibits that kind of sensible monetisation straegy for now (I think).
Think photoshop before, the model that clip studio pro has 'reverted' back to (I support it, but I can't help but remember that time when they bombed twitter with adverts with a deal - that's money that didn't go towards development).
The Free Software movement has nothing to do with price. It's about freedom. We deserve to have the freedom to control our own devices. Proprietary software takes that away, so it's unethical.
It's shame, if only the ideology wasn't born in an anglophone country maybe this common misconception would have never been a thing in the first place.