I actually remember male cheerleaders at my high school in the 1960's.
Here is an excerpt from "Pacific Standard" magazine online:
"You might be surprised to learn that at its inception in the mid-1800s cheerleading was an all-male sport. Characterized by gymnastics, stunts, and crowd leadership, cheerleading was considered equivalent in prestige to an American flagship of masculinity, football. As the editors of Nation saw it in 1911: "The reputation of having been a valiant 'cheer-leader' is one of the most valuable things a boy can take away from college. As a title to promotion in professional or public life, it ranks hardly second to that of having been a quarterback."
Indeed, cheerleading helped launch the political careers of three U.S. presidents; Dwight D. Eisenhower, Franklin Roosevelt, and Ronald Reagan were cheerleaders. Actor Jimmy Stewart was head cheerleader at Princeton. Republican leader Trent Lott was a noted cheerleader at the University of Mississippi."
The men doing it might be looking for an excuse to be interacting with the girls in such a way, and the girls might end up feeling uncomfortable as a result.