If we're being serious? Because AoXM features the actual 616 characters running around in X-Man's little hamsterball, as opposed this being to a full-on what-if or actual AU. For example, when Pak and Van Lente wanted to show Hercules a bi/pan in Pak's Incredible Herc run, they had to imply everything as opposed to telling or showing because, iirc, editorial wouldn't go for it. But Greg Pak could get away with Herc and Howlett have a full-on snog session on-page in his X-Treme X-Men run because they weren't the "real" Hercules and Wolverine.