That's not really a use case for [sic]. As per wikipedia: erroneous or archaic spelling, surprising assertion, faulty reasoning, or other matter that might otherwise be taken as an error of transcription.

One or both of these use

> archaic spelling

> other matter that might otherwise be taken as an error of transcription

fit the description though the case for archaic spelling is arguable.

Both the US English and British English spellings are used extensively, nobody would think it's a spelling mistake. And calling British English archaic is quite insulting, it would be like calling US English "dumbed down".

AmE and BrE are both used simultaneously in online spaces. Neither needs to be corrected or (sic)'d to the other.