A bit, but I justify it by saying when I went to one of their multi group concerts in Busan, I could not tell the difference in music style, look, or anything else, and I don't see it as any way indicative of Koreans or Korean culture.
Sure, but for those 2 groups, you also have Sistar, Kara, T-ara, Girls Generation, Girls Day, A-pink, Miss A, AoA, Gfriend, Nine Muses... I'm probably missing like 20 or so other relatively large groups.
And guess what, they all have leggy girls, usually 4, though lately 5+ are becoming more common. Yea, they do look good. just as the surgeons made them. The girls usually don't actually sing at performances, and often they aren't the actual singers are only there to look pretty and lipsync. They all were created by the same 4 or so big recording studios in South Korea. They all are surrounded by unconfirmed rumors that the girls only got to be in the groups by having sex with producers from said 4 big studios.
Literally, when I saw the image, I thought, 'oh, I guess Sistar changed their hair styles a bit since I saw them perform live.', But as you said, this is a completely different group.
I will say, 2ne1, F(x), and Boa on the girl group side, and Big Bang and Super Junior and Psy do stand out as a different from the others and genuinely talanted. Still, the best music I've heard out of Korea was from a group of street performers, not one of these corporate monstrosities.