Open source maintainers aren't a source of limitless unpaid labor.
You believe in sharing, but you don't want to be taken advantage of by money-making machines that don't.
Dual-licensing your code lets you stay true to your roots while earning grocery money from companies that can spare it. 💰
What's dual licensing?
Dual licensing is saying to the user "here, you choose between these two licenses". One costs nothing but has restrictions, like the consuming project must be open source (GPL) or not make money (Creative Commons). The other has no such restrictions but puts a few dollars in your pocket.