The one thing that always struck me as crazy given the 24th century tech we were shown was the whole "Dtat is unique and can't be replicated..." bit.
The what? Who wanted to replicate Data? That he wasn't replicated simply tells us that there was no interest in doing so.
Maddox wanted to understand how Data works. Replicating him would get Maddox no closer to that goal; he'd face the same legal-ethical hurdles in vivisecting the second Data as he did with the first.
I didn't see any "Data is sooo unique! thing" in TNG. Apart from Maddox, nobody from the Federation or its chief adversaries is interested in him there. Him being an android prompts reactions of "How quaint!" and general disdain, except with one provincial robotics enthusiast and one excitable doctor. He isn't taken in for study, but instead allowed to drift into Starfleet, of all things. In true Foreign Legion fashion, he's accepted in without anybody bothering to check whether he's sentient, or caring much. Even though he looks like Noonian Soong, nobody really connects him to that fellah, suggesting that androids can be built literally as jokes, pranks, expendable mockeries of a ridiculed mechanical man maker. And nobody bothers to study him even to the minimal degree it would take to detect the telltale positronic signal that he supposedly emits, just like B-4 (only probably weaker, him not being a leaky early prototype or a cheap Romulan copy thereof). So again no connection to Soong's infamous work on positronics is made.
None of this is contradictory or unexpected - not if we assume that androids are regarded a useless and outdated technology and a dead end in producing practical AI lifeforms. Perhaps the introduction, proliferation and improvement of holograms made AI research switch tracks and abandon machine men?
Plus, Soong remade his own Wife as a fully functional/virtually indistinguishable from a human being as a fully functional android (IE - He perfected the process) - See TNG S7 - "Inheritance". It's just crazy to me to believe Soong did it "All for himself" - and wouldn't share or archive the procedure anywhere in the known Galaxy.
Remember that he was laughed out of the court originally. He clearly only wanted to make his comeback when he had an absolutely perfect product to demonstrate. And neither Lore nor Data were fit for release - both got out by accident. Juliana might have been considered imperfect as well. And certainly Soong would not wish to share any of his secrets until he could humiliate the entire scientific community with them.
Timo Saloniemi
