User blog comment:MasterBroccoli/Naming and Linking (Capital Letters)/@comment-26842175-20170926090500/@comment-1365532-20170926095805

The rationale for American spelling is that it's aligned with spelling made by developers of the series. Quite a few of us (myself included) come from countries that prefer the British style, but I'm sure the switching the spellings to American style proper can be done without much difficulty.