Because it's the first step to attracting new retards. Neo nazis & the far-right don't lie about things for no reason, they know their position is absurd but they also know they will attract almost no-one to the cause by going straight to "Jews deserved it, it needs to happen again".
Step 1 is lie, say it never happened and pretend you're "just asking questions", to attract retards, racists, incels looking for someone who will listen to their whining. Retard might be a incel, a moronic slav who has nothing in their life of value, a gamer wehraboo etc.
Step 2 is invite them into a 'newbie friendly' discussion or group, but continue to slowly raise the power level of discussions with said retards, until you're ready to hit them with Step 3.
Step 3 is to abandon the lie, admit that it happened, but because of what you've primed the retard with in Step 2, it was "the right thing to do". Retard will accept this, even if he doesn't actually believe it yet, because he doesn't want to lose his new friends.
