The 1920 Nazi program is vague on some things.
The NSDAP in 1928 felt it necessary to include an explanatory note on point 17.
It took over power in Germany in 1933.
"We demand a land reform suitable to our national requirements, the passing of a law for the expropriation of land for communal purposes without compensation; the abolition of ground rent, and the prohibition of all speculation in land."
Hence this clarification:
It is about acknowledging complexity, and not about reading one source—the 25 point program as written in 1920—to explain an ideology across decades.
But then there are also these other statements.
At the basic level, historians make sure not to confuse a term in a primary source (like someone saying/writing "I'm a socialist") with an analytical term— one that has a meaning that's been arrived at by studying many sources ("socialism").
What someone (a person, an organization, etc.) says they are (do, want, etc.) can only mean something if it is taken in context.
That's sometimes quite tricky.
History is making sense of what happened.
Here's a clue:
papers.ssrn.com/sol3/papers.cf…
"[T]he last governments in the Weimar Republic took over firms in diverse sectors. Later, the Nazi regime transferred public ownership and public services to the private sector. …