Thanks for the write up and I think I learned a lot of stuff. But at the same time I think you’re getting a bit hung up on the particular word “diamondoid”. It’s normal in language for words to have different meanings in a base-level language versus in particular specialized jargons. For instance “speed” and “velocity” are synonyms in normal English but in physics jargon they’re distinct. As Kuhn famously noted whether a lone helium atom counts as a “molecule” or not depends on whether one is speaking chemistry jargon or physics jargon (with general English not being precise enough to give an answer). And very few people would consider carbon a “metal” but that’s just what it, along with every element heavier than helium, is called in astronomy jargon.
In general, in English, if you have a base word you can append the suffix “-oid” to create a new word that means “something similar to the base word without being it”. So you might properly call a bean bag a “chairoid”, something with many important chair properties without being a chair. And often these constructions get taken up and given precise meanings in different formal jargons for words like “sphereoid”, “planetoid”, or apparently “diamondoid”.
As general practice I think it’s good to avoid stepping on precise meanings in jargon when you’re aware of them and there’s another word that works as well. Use “speed” rather than “velocity” and call a rhombohedron “cube-like” rather than “cuboid”. But at the same time I don’t think it’s a very bad mistake to use a word that makes sense in non-jargon English in a way that conflicts with established jargon. And if someone uses a word in a way that doesn’t make sense in jargon terms but does in ordinary English usually its best to go for the non-jargon interpretation.
Also, even if the secret information that decision makers have isn’t decisive there will still be a tendency for people with secret information to discount the opinions of people without access to that information.