Not to ruin a good argument (purebloods has a distasteful afterlife) but it was the vaccinated and their pushers promoting the unvaccinated were the killers of the elderly, weak and children by not getting the shot like good little Germans, er... Citizens.
We were the demonized minority and got punished for our beliefs
But, still mudbloods is offensive connotations.
We The Unvaxxed
Are Pissed, the Vaxxed
Should be Scared.
If Pureblood sounds too Nazi, which point I can see, use another with the same meaning. Cleanblood might work. Unpolluted blood is too cumbersome.