I think they are publically calling on other members not to attempt a fillibuster to make themselves look more moderate. This is all posturing, the hearings, the whole works. Kennedy, Shumer and company made a public spectacle of themselves that didn't play well with anyone but the radical left during the hearings. It was all over for them with the middle when Judge Alito's wife left the hearing in tears and Schumer went on TV defending the kind of questioning that provoked that response from her.
They know they don't have the votes to make a fillibuster work, any attempt would just make them look more impotent and like spoilt little children. So by making this statement DiFi is distancing herself from the line of questioning at the hearings. I have no doubt that if they thought they could stop the nomination, they would fillibuster.
Jeff