As far as I can tell from online comments, both monarchists and republicans appear to be spluttering over people saying that Charles III has been "coronated."
"The word is 'crowned,' not 'coronated.' " " 'Coronated' is not a word." " 'Coronated' is a bastard back-formation from 'coronation.' " Someone quotes Paul Brians saying that it only means "crown-shaped" and is legitimately used only in biology.
I hardly ever recommend that people switch to decaf, but this might be the occasion.
Coronate has been a word in English since the early 17th century, with a citation from 1626.
It derives from the Latin coronatus, past participle of coronare, "to crown."
The Oxford English Dictionary lists it, saying that it is a relatively rare word. Merriam-Webster includes it, defining it as "to crown." Its rarity might be attributed to the lack of a major coronation to cover over the past seventy years.
Merriam-Webster's Dictionary of English Usage quotes The Wall Street Journal of February 9, 1952: "Queen Elizabeth II will probably be coronated sometime between August and the spring of 1953."
So it is a word, an English word in use.
You do not much like it; you do not like it at all; you despise it and the people who use it.
Your futile protest has been noted.