One of the four fair use factors is the portion of the copyrighted work that was taken. For a finding of fair use under this factor, the infringing work must only take the amount of copyrighted material needed for the infringing work’s purpose.
If they ripped every single file they have access to, there’s no way to be found as fair use under this factor. If they argue they were using a curated list of only the works they needed to develop their model it could be fair use, but admitting to taking every possible work in their entirety is a surefire way to fail a fair use defense.