Kenneth “The Machine” Alexander, a professional mixed martial arts fighter who headlined a free event for Marines Friday night at Camp Pendleton, Calif., has been less than sincere with the media about the details of his military background. Multiple reports documenting Alexander’s rise in the MMA world (here’s one and here’s another) have suggested the former Marine staff sergeant was a real stud when he served — a sniper with a Special Forces affiliation and multiple combat tours in Afghanistan and Iraq. Um … not exactly, he told Marine Corps Times this week. Acting on a tip from an alert reader, we…