...because it appears you are using an out of date offline copy of the page to make your edits, and then pasting it into the edit window in its entirety. Doing so results in you undoing any edits made by anyone else since you acquired or created that copy -- including those made by admins for style and usage reasons. In other words, this is another case of you edit-warring with a mod. Per Robkelk's notice below, you are now subject to a one-week tempban.
When you come back, we strongly suggest that you consider the possibility that someone other than you might be editing these pages and that your changes should include theirs, not undo them. If you persist in behaving as though you're the only person who could possibly edit "The Lighthouse" and other pages in which you have an interest, you will receive further and longer tempbans until you either get the point, or you earn a permanent ban. (And it doesn't take very many tempbans to work up to a permban.)
-- Looney Toons, admin