Personally, I'm grateful to be corrected on a casual and anonymous forum if it saves me from making the same mistake on a formal document, condescension notwithstanding. My response to grammar cops is either, "Thank you!" if it was due to my ignorance, or "Oops, damned autocorrect/typo/ brain fart," if a lack of attention was at fault.

This specific one is so common, are people actually mistyping or getting autocompleted? flashbacks to Rouge One

And the worst are those people that make people feel bad for correcting spelling mistakes!

There are also many people that continue to make easily correctable mistakes because they don't know any better.