Freedom is the ability to use the open source code without any restrictions. Copyleft licences restrict the freedom. These licences sound good in theory (let's prevent from unpaid use of the code in proprietary products!), but they work not so good in practice (why bothering with legal headache related to copyleft-licensed code if it is easier to use BSD-licensed code?). This prevents from wide adoption of copyleft-licensed products.
You're misinterpreting it. Integrating FOSS code into a proprietary product is what restricts the user's freedom. Copyleft licenses prevent this restriction. And yes, indeed, why bother working for freedom if it's easier to not have freedom?
> Integrating FOSS code into a proprietary product is what restricts the user's freedom. Copyleft licenses prevent this restriction.
This is like saying "black is white".
Users are free to use any products - open source and proprietary. They don't care about licenses most of the time - they prefer the product with better usability. Copyleft licenses prevent from creating proprietary product with better usability on top of open-source product with mediocre usability. E.g. copyleft licenses restrict users' freedom to use the best product - they force users dealing with the mediocre product.
Take a simpler example. If you have the freedom to imprison me for no reason, you can take away my (literal) freedom. Now you are free, but I am not. Because of this imbalance, the freedom to arbitrarily imprison people is an unreasonable one. Everyone should have as much freedom as possible, and everyone should have the same "amount" of freedom, if you will, so restricting others is out of scope. It's not just about your own freedom, don't be selfish! And besides, what ethically good person would want to lock people up for no reason?
When you are creating proprietary software, you are asking your users to let them be oppressed by you. You are asking them to give in to potential surveillance, planned obsolescence, manipulation, extortion and a variety of other injustices. And when you charge a price for your proprietary application, you are asking your users to pay for this mistreatment. What value does "the best product" really have, when you pay for it with your wallet and your freedom?
Your antique monetization scheme does not align with the values of Free Software. Should you restrict your users' freedom, or fix your monetization scheme?
