I imagine the planning meeting for this book went something like this:
"So we have a ridiculous male lead, a second in command with glasses and an analytical attitude, a pair of red-headed twins, a single girl, and a guy with long blonde hair who looks like a girl, but surely there is something we could do to be more like Ouran Host Club."
"We should have a chapter where the boys have to actually act like a host club!"
"Good idea. If we added an adorable little-boy ninja, someone might catch on."
Still, if it works, why mess with it?