They clearly expected the leak, they distributed it very widely to researchers. The important thing is the licence, not the access: you are not allowed to use it for commercial purpose.
So either, it is very hypocrite of them to apply DCMA while the model itself is illegal. Or, they are trying to somewhat stop spreading as they know it is illegal.
Anyways, since the training code and data sources are opensource, you 'could' have trained it yourself. But even then, you are still at risk for the pirated books part.
This gives the company plausible deniability while still allowing ~unrestricted growth.
Persistent storage (in violation of TOS) and illicit use of Facebook users’ personal data was available to app developers for a long time.
It encouraged development of viral applications while throwing off massive value to those willing to break the published rules.
This resulted in outsized and unexpected repercussions though, including the Cambridge Analytica scandal.
People should be wary of the development as much as they are enthused. The power is immense and potential for abuse far from understood.
For example, WhatsApp’s greyhat use of smartphone address book.
The US government also has a stake in unbridled growth seems, in general, to give a pass to business exploring new terrain.