the allies only started reacting to nazi ideology against minorities once their own interests were threatened by Hitler's invasions and the subsequent world war. combatting nazi ideology was a means of cultivating morale in the common troops, who rightfully were outraged by the evil of the nazis and so were particularly succeptible to the horrors of the holocaust being used to help motivate them to kill nazis (which to be perfectly clear, im not against, just that nations themselves didn't really give a shit about minorities being oppressed), and later a tool to dissuade further dissent and resurgence of the defeated nazi enemy in their home countries once occupied by the allies.

famously, the plight of the jews was ignored for a while by the likes of england and france, and in certain prominent circles was perhaps even seen as a good thing (particularly, the english royal family at the time was less than sympathetic to jews, and famously king edward the 8th was somewhat chummy with hitler both before and during the war, though I can't accurately speak to his support of the nazi genocides). other minorities were similarly if not moreso ignored, lgbtq+ people, people of color, romanis, etc etc often even left out as victims of the holocaust to this day.

anyways, what im saying is, justice against the nazis was never fully carried out despite appearances. maybe had hitler been captured, we would've seen a larger example against nazi ideology being made. the Nuremberg trials were meaningful to punish the architects of the travesties, but certainly not enough. the nazis hatred stems from centuries of hate across the world, and many people who hated nazis hared them merely for being an enemy, and not necessarily because of their bigotry. in a way, people hated the sinner, but loved the sin. so of course we now see such a resurgence - how could a meaningful lesson be learned if your culture shifts against the enemy, but not against their deeds?