The value of copyleft licenses, for me, was that we were fighting back against the notion of copyright. That you couldn't sell me a product that I wasn't allowed to modify and share my modifications back with others. The right to modify and redistribute transitively though the software license gave a "virality" to software freedom.
If training a NN against a GPL licensed code "launders" away the copyleft license, isn't that a good thing for software freedom? If you can launder away a copyleft license, why couldn't you launder away a proprietary license? If training a NN is fair use, couldn't we bring proprietary software into the commons using this?
It seems like the end goal of copyleft was to fight back against copyright, not to have copyleft. Tools like copilot seem to be an exceptionally powerful tool (perhaps more powerful than the GPL) for liberating software.
What am I missing?