There is some clear disapproval of Grok's capabilities in the end of the second section:

> X Corp.’s flagship product since its identity change—a generative AI model called Grok—has created shocking amounts of child sexual abuse material (“CSAM”) and other nonconsensual sexual imagery. X Corp.’s generation of CSAM and other nonconsensual imagery was so egregious that it sparked several investigations and lawsuits, including by a bipartisan coalition of 35 state attorneys general and international law enforcement.

I guess it is complicated by the context that the letter goes on to claim that these capabilities were partly enabled by misuse of personal data (the underlying issue before the FTC here), which leaves open some possibility that EFF would agree that X should not be liable for users' use of Grok if it had been created by some other means.