The minute you see Linux kernel sources, your future output is not forever tainted by the GPL.
It's one thing if they've overfit. But we're still so early in this. It would suck to let the Luddites kill a technological development perhaps on par with or even greater than the Internet itself.
Where are these same voices when artists' output serves as the training set? Or novels? Or forum posts?
If this lawsuit succeeds, we'll cut ourselves off at the knees too. We won't be able to develop models either due to the mishmash of licenses.