[tyingq]

GitHub mentions that they don't currently look at the license before trawling code.

https://twitter.com/NoraDotCodes/status/1412741339771461635

There's also other references that GitHub public repos weren't the only source. They trawl other publicly readable code.

[nextlevelwizard]

You can sue them for using your code if they break the licensing agreement. Contact EFF and they'll set you up with a lawyer.