Don’t be an asshole: an editor’s guide to internet etiquette
When I took my first editing course, our instructor gave us a valuable piece of advice:
Don’t correct someone else’s grammar/spelling on social media. Ever.
Facebook, Instagram, Reddit, LinkedIn, and internet forums (are they still A Thing? I am old) are the textual equivalent of a casual conversation, often with people you don’t know well (or at all).
Do you stop a relative stranger mid-conversation to correct their grammar? No, you do not. And you don’t because that’s a douche move.
Similarly, unless specifically asked, don’t correct someone on social media unless they ask you to. It’s also a douche move. Use your superpowers for good.
I adhere to this policy…with one exception:
If someone else corrects someone on social media and they happen to be wrong, then all bets are off.
I say that, if someone else is abusing their superpowers (or perceived superpowers), feel free to jump in there and tear them a new grammatical/orthographic asshole. Back it up with quotes from dictionaries, style guides, grammatical textbooks, whatever you need.
Make them regret the day they ever picked on the poor original poster. Really give them hell.
And then (and this is key), explain that correcting spelling/grammar in a casual online forum is what assholes do. Tell them grammar teachers say so. Don’t be an asshole, pedantic Facebook-corrector. No one asked you.
End rant.