I can acknowledge that some Poles were Fascist collaborators while also condemning the Fascist colonisation of Poland, much like how I can acknowledge that some Jews were Herzlians, heterosexists, antiziganists, anti-Sephardi, or outright Axis collaborators, yet condemn the Shoah anyway. I have the common sense to tell that populicide is not the appropriate penalty for someone’s bigotry or other mistakes.
Then again, maybe anticommunists deny or excuse Polish antisemitism because they believe that merciless extermination is the only answer to someone’s bigotry. Given how often they bring up (and overstate) Palestinian heterosexism as if that somehow justifies the IOF’s extermination campaign, that does not sound like too cynical of a suggestion.