>Is there even a modern nazi ideology?
No, or at least it is so fringe you won't ever hear about it.
After '45 both sides (the liberal West and the socialist East) so heavily marginalized any group and thought that has anything to do with nationalism (a sub branch of it is national socialism) it can be considered eradicated. They created a false picture of nationalism and shifted all the blame to that, and even in our day and age everything bad is blamed on nationalism, even tho in the last ~80 years liberalism and socialism shaped the history and the events happening.
>I doubt that the majority of people that are labelled nazis want any form of socialism of fascism as their government.
You doubt it rightly so. Most people labelled as nazis are classical liberal and at most patriot which has little to do with nationalism (you could be patriot during the reactionary absolutist times - don't forget nationalism was a revolutionary idea along with liberalism and socialism back then). Labeling people nazis is a way of marginalizing them, and push away people from around them, because most people will get scared they also will be labeled as nazi.
This is the classical, so called "salami tactic": imagine you are on the left and you want power. You turn towards the right and you point at the very end of it and you call 'em nazis. Everyone left of them will get scared and will disown them, and won't make business with them anymore. They will be ostracized, won't get elected into offices, noone will publish their thoughts. You just cut off a slice from the salami.
Now you point at the next group on the very end of the political salami, and you call 'em nazi. Everyone left of them will get scared and will disown them, they get ostracized, yaddi yaddi yada. Slice chopped.
Again, the next on the furthermost, and the next, and the next. One after another you chop off the peasants, the christians, the conservatives, the liberals, the socdems, the socialists, and even the commies, until only the your clique of bolsheviks remain in politics.