Suspected white supremacist is not trite and the semantics is necessary.
If you think suspected white supremacist is over used, then you should talk to the people who classifies themselves as white and tell them to tell the victims of white supremacy, that they are in fact white supremacist, so we can call them white supremacist and not suspected white supremacist.
Because your problem is not with neely fuller or tariq using 'suspected white supremacist,' your problem is with the people classifing themselves as white, who practice white supremacy, not saying their white supremacist.
If the people who classify themselves as white and practice white supremacy, said they were white supremacist, then people like neely fuller and tairq, would not have to suspect them of being white supremacist.