I've never met a white supremacist who had a high IQ (or much in the way of literacy skills or remarkable education) and in terms of IQ tests, they are not an accurate test of intelligence anyway because, as I had a university professor point out many years ago, IQ tests are not geared towards people that answer questions on the test patiently, thoughtfully, or cautiously or if they take time to ponder the questions, double-check, etc. They are only geared for people that rush through the questions and right or wrong answers be damned. So, IQ tests can be a useful tool, but are not the be all and end all when learned skills, content of character, and merit are what count in the end.
I've known plenty of high IQ people, including high IQ white people, who never did anything of significance with their lives. There were no Einstein's, Tesla's, etc. among them. They had average jobs and careers and that's fine because they were happy and decent people.
IQ tests are not just geared toward math or language skills, but also pattern recognition and three-dimensional spatial relations skills. For example, my pattern recognition and three-dimensional spatial relations were off the charts when I took an IQ test which were better than 85% of the population of the planet while my vocabulary skills at that time were just average or only slightly above average.
There are plenty of people that struggled in school, but they are outstanding mechanics or plumbers or electricians, etc. that found something they were great at doing and they ran with it.
So, stop obsessing about race (because that is RACIST) and stop thinking about white IQ's versus black IQ's because the fact remains that China produces far more people with high genius-level IQ's than in any other part of the world (but those "geniuses" were dumb enough to love Communism in China) and Asians often have higher IQ's than whites. Jews also have high IQ's for the most part and that was not always the case because IQ's can increase substantially within one generation with proper health, nutrition, and various genetic or environmental reasons.
So, you want to generalize that blacks are not as intelligent as whites (and let's face it that BLM rioters, looters, arsonists, thugs, and murderers are subintelligent), but white Antifa losers and members of white supremacist groups, the KKK, the Alt-Right, etc are not making whites look terribly intelligent if one wanted to make broad and inaccurate generalizations.