Now, it is clear that the decline of a language must ultimately have political and economic causes: it is not due simply to the bad influence of this or that individual writer. But an effect can become a cause, reinforcing the original cause and producing the same effect in an intensified form, and so on indefinitely. A man may take to drink because he feels himself to be a failure, and then fail all the more completely because he drinks. It is rather the same thing that is happening to the English language. It becomes ugly and inaccurate because our thoughts are foolish, but the slovenliness of our language makes it easier for us to have foolish thoughts. The point is that the process is reversible.
~ George Orwell,"Politics And The English Language" (1946)The American Chemical Society (ACS) maintains a data base for each and every unique chemical substance. Currently, more than 102 million organic and inorganic substances and 66 million protein and DNA sequences fill the ever-growing data base. But only "real" chemical species get registry numbers. A separate and distinct data base houses "hypothetical" chemical species. Hypothetical chemical species exist because chemists (more often patent attorneys) often claim genuses (genera) of species without naming each and every species. One reason to do this is to avoid being copycatted by some trivial variant of an invention. So there are both "real" and "unreal" chemical substances. It is a bit like the difference between real property (estate) and intellectual property. A similar dichotomy exists in language.
Verbs have "moods." One of them is for stating facts;* another is for voicing commands; yet another, called the subjunctive,** is for stating wishes and non-facts. We are losing the subjunctive. It is pedantic to bemoan the loss of a mere verb form; it's altogether another thing to dismiss the line between fact and fantasy. But that is what's happening.
"X alleges that Y did Z" becomes simply "Y did Z."
*As the fossilized metaphor "indicative" preserves, the indicative mood allows the speaker to point out facts in writing or conversation. When there is doubt or uncertainty in the mind of the speaker, i.e., when you shouldn't be pointing, use the subjunctive mood.
**The Latin modus subiunctivus probably is a translation of Greek hypotaktike enklisis -- literally, "subordinated mood" -- so-called because the Greek subjunctive mood is used almost exclusively in subordinate clauses. We do the same thing.