Where did that come from?
Obviously those "traditionalists" don't know what they are talking about. While AKB48 is the most successful "female" idols to date (there is always SMAP, Arashi, and Exile on male side), they are not the first one and they won't be the last. The whole idol industry can even be trace back to 70s as well and have impacted the culture even back than.
Anyway, that picture is awesome. If I remember, it is from one of AKB's variety shows, AKBingo. It was an episode inspired by last years summer drama Rebound that had Takamina, Tomochin, Mii-chan, Mariko, and Kojiharu dressed up in sumo suit in a series of competitive games.
There the screenshot from that episode:
Spoiler for AKBingo:
Five of the six oldest members in sumo suits with special makeup:
The only exception is in LMAO mode:
