Stack Exchange specifically has a policy that localized English spellings shouldn't be edited to American English standards. The only exception to this is in tagging, which follows American English spelling and terminology in the interest of tagging simplification.
It is worth noting that many of these edits may be due to an honest mistake. Many people are unaware of the differences in British English and American English spelling conventions, so assume that they're trying to be helpful rather than antagonistic.
So, what can you do if an edit is only changing your local English spelling? You have a few options.
- If you're reviewing the edit, reject it using the "no improvement whatsoever" reason or a custom reason explaining that British English is acceptable here.
- If you're the OP of the post, you can reject the edit suggestion even after it's been accepted by other users (with certain caveats, as explained here). Moderators also have this option.
- If the edit has already gone through, roll it back.
- If you're editing - just don't! Realize that we don't require American English in post titles or bodies here. Learn to love diversity in language!
Otherwise, be sure to consider any other edits that were made as, along with the localized spelling, there may have been valuable information added or clarifications made. In these cases, rolling back may remove content that belongs there, so consider editing the spelling back to what it was rather than rolling back and losing the new information.