This blog has no editor. I write without the protection of an additional set of eyes and expert advice. So any editing beyond my own, as I have mentioned, is crowdsourced, affording readers the glee of correcting a copy editor. Few resist.
Some of those corrections are made discreetly, by polite private messages. Some are posted publicly, and I don’t mind. Freed from the burden of omniscience, I accept correction gladly, and with gratitude. I write for publication, and those who make public performances must learn to expect and accept public criticism.*
But public correction is not always appropriate.
Correcting another’s pronunciation or spoken grammar without invitation has always been considered officious, if not outright rude. If done in company, it is doubly officious and rude.
And there is an etiquette for the middle ground between private conversation and public performance, such as the realm of office email and online discussion groups. Proclaiming in a reply-all message or posting to an entire group that you have spotted a typographical error or solecism (a) is like appropriating Nelson Muntz’s HAH-hah from The Simpsons and (b) wasting the group’s time. If you see something amiss, quietly and privately inform the writer.
Did you have an English teacher who corrected your grammar or pronunciation in front of the entire class? Did you enjoy that? Did you aspire to be like that teacher? You could have chosen a better path.
*Which is why I also offer it when people who purport to be professionals publish shoddy work. That’s legitimate.