National Socialism specifically, and Fascism in general, has never been adequately defined - that is because it was negatively conceptualized as a reaction-against Communism.
When Fascism arose, just after the Russian Revolution, Communism was an urgent and imminent threat. To be anti-Communist was, for many people - indeed significant majorities in some countries - sufficient; so Fascism and National Socialism attracted powerful and highly-motivated supporters.
Such supporters were drawn from a wide spectrum of anti-Communists, including religious groups and persons; but Fascism and National Socialism were themselves secular parties, with secular priorities - they did not envisage running the state according to and within religious priorities.
So, National Socialism seemed OK because they were against the primary threat of Communism; but, of course, they weren't OK.
Update to now - modern secular reaction is also negatively conceptualized and secular - being against the New Left/ Feminism/ Antiracism/ Political Correctness/ Social Justice Warriors and the rest of it.
But the difference is that New Leftism is not new (its dominance dates from the middle 1960s), nor is its threat urgent and immediate - not least because New Leftism is The Establishment.
Therefore, (unlike Fascism and National Socialism) reaction against the New Left is not powerful, nor is it a majority, nor is it highly-motivated.
Furthermore, it may seem that any party who is against the insane evils of the New Left is OK, just what we need. We might even be tempted to wish for a secular reactionary revolution. But - even if there was sufficient support for it to happen - any anti-Left party with secular priorities that attained power would surely go the same way as National Socialism or Fascism - why not?
Do not tempt fate by thinking, or saying, 'anything is better than' or 'things can't get worse'... That is a sure and certain path to things becoming very bad, very swiftly.