Yeah, I'm going to have to disagree with this.
HP Lovecraft, MAR (Phil) Barker, Gary Gygax . . . all complicated people, in the same sense that we are all complicated people. Having aspects of your personality and beliefs be problematic doesn't make you automatically a "horrible person", nor does it make folks who admire you "horrible people".
HP Lovecraft was hella racist. He was also mentally ill. He was a miserable man leading a miserable life. You can be a fan of Lovecraft's work, and even admire the man, while still acknowledging and rejecting his racism. I respect and admire Lovecraft as an author, I feel sorry for him as a person, and his embrace of racist ideas saddens me. I doubt I would have enjoyed his company or friendship if we lived at the same time and place.
Gary Gygax was "grandpa-racist" and "grandpa-sexist" . . . he held the kinds of racist and sexist views common amongst white dudes of his time. I doubt Gygax considered himself racist or sexist, and his views were shaped by his upbringing and experiences. Doesn't excuse them, of course. Gygax, IMO, wasn't even that great of a game designer, he just happened to capture lightning-in-a-bottle with Dave Arneson. I don't have a great deal of admiration for Gygax as an artist or designer, although I do respect and am grateful for his contribution to my favorite hobby. Gygax was not a horrible person . . . but also not worthy of hero worship either, IMO. So many better game designers in our hobby, both as designers and as people.
MAR Barker, Phil, was an odd academic who created a detailed world that appeals to a very small fanbase. Even before we learned of his involvement with racism, I wasn't much of a fan of his work as an author and world-builder. Without defending his actions, we still don't know a lot of the details of exactly HOW racist he was, but we know enough to be saddened and uncomfortable with his work. Being on the editorial board of a problematic academic journal isn't a good look, but isn't proof Barker was a Nazi-sympathizer. His "secret" novel isn't necessarily either, I'd have to read it or read a synopsis/review from a trusted source to judge . . . but it's not worth the effort to find out. Barker may have been no more or less racist than other white academic dudes of his time, but harbored odd ideas of how to engage or deal with Nazism. His novel, regardless of his reasons for writing it, is highly problematic. I wasn't impressed with him before, I'm less so now, but I'm also not willing to judge him as a secret Nazi-sympathizer quite yet. Barker might have been a horrible person, but I don't know enough to judge him yet, and I also don't care enough to dig deeper. His impact on society is limited. I actually was recently considering picking up his Tekumel novels out of curiosity . . . but my interest has soured, after this recent news about the man.
My mixed views on Lovecraft, Gygax, and Barker doesn't make me a horrible person, an apologist for horrible people, a sexist, racist, or a Nazi apologist. If any of these gentlemen were still alive today, I wouldn't be engaging with them, I likely wouldn't be purchasing their works, I wouldn't be attending conventions with them as major guests. But I also don't feel the need to put them in the neat little boxes of "horrible person".