I think the problem there is that a shit load of people are so uneducated that they don't associate nationalism with the nazis, they only associate the holocaust as the bad thing they did and really don't understand that ultranationalist ideology will lead to a repeat of what occurred over and over again. Thus it becomes much easier to just say nazi when referring to these ultranationalists even though it's technically incorrect when the ultranationalism they support is actually polish, or american, or fucking italian, idk etc etc etc. They're all have pretty much the same goals just in a different set of completely made up lines on a map.