That's what you were talking about earlier with the general acceptance of other types of bike.
Everybody has their own view of what their optimum motorcycle is. I personally don't have any interest in the motorcycles that place style over engineering, such as those that strictly follow dogmatic historical design, for the sake of being "classic" at the expense of the actual riding experience. I dunno about you, but I can't remember the last time I went on a ride and stared at the motorbike between my legs the whole time as the world rushed past me!
I think that a top tank to brace yourself to the bike with versus a step through offers an increased amount of control. Mopeds have small wheels and ride low so most people don't have a hard time sliding over the back versus the front. I don't remember ever approaching a bike and going for swinging a foot over the front. On scooters the step through classifies it with floorboards for legality, on a moped, well, um.
That's my 2 cents I'll exit stage left now, because I know how it goes...