If knowledge is to be free, then any corporate/commercial interest that locks up modified knowledge (code) to run their own services should have that locked-up knowledge freed from their commercial silo as well.
In the case of AI, I don’t think LLM providers are required to make their models completely open source just because they were trained on the data freely available on the internet. Those model weights aren’t the original data anyways, so they aren’t even selling access to that original data. However, there is should be nothing preventing others from creating and selling something produced from those LLMs. Distillation, for example, is free game.
In short, you should be required to make your knowledge freely available. But once someone has access to that knowledge, you can’t stop them from using it however they wish, including if they wish to sell it themselves.