Churchill's legacy is more complex that just "he had racist viewpoints, but everybody had that back then." He was an imperialist who believed in Britains right to conquer and rule inferior people around the world. He was bitterly opposed to dismantling the Empire. Even
after WWII, he was responsible the the horrifically brutal suppression of the rebellious Mau Mau in Kenya, which included the use of concentration camps. Yes, this happend
after the Nürnberg trials.
So while he is rightfully remembered as a hero for opposing the Nazis when few others did, he also did much of the same the Nazis did, just far from Europe and against non-white people.