They are trying to impose guilt by association in the eyes of the public. If Trump is being sued with the proud boys, then the media can claim that Trump is allying with "Domestic terrorists" in court and will claim Trump has ties to the Proud Boys because they were sued together by the NAACP. Doesn't matter if he actually has any ties or not, and it clearly doesn't matter that the proud boys are being unfairly maligned by the media, because the normies will not do independent research on any of it.