Suno can’t prevent humans from copying other humans, it can only make sure that the direct output of its system isn’t infringing.
In this context, this would be the equivalent of Suno explicitly placing stop points throughout the training, tokenization, and generation processes to verify that there was absolutely no chance of it generating copyrighted material through some kind of clean room reconstruction test. They would also need those tests to be audited at random by a third party governing body. Obviously they are not doing this, so the metaphor definitely does not track here.
Anything remotely beyond that and we have teams of humans adjudicating specific cases: https://library.mi.edu/musiccopyright/currentcases
Surely, for Suno to claim fair usage and be given free reign to build a commercial business off of literally anyone's original works then the bare minimum bar for allowing that usage would be: make a satisfactory test to prove that you're always doing something transformative and original, within practical limits.