I'm a 20-year-old American girl studying abroad at Korea University in Seoul this semester. After living here for five months and talking to many Koreans (mostly my college aged peers), I've made several observations about K-Pop and Korea that are completely at odds with the international K-pop perspective, which I've detailed below for your pleasure.
Keep in mind that my frame of reference is 19-24 year-olds.
Most people outgrow K-Pop after middle school. Some people are fans throughout high school but it rarely lasts after that. As a result, a large majority of idol fanbases are middle school girls, which means all the ~scandal reactions~ and netizen comments you read are left by prepubescents. The general public does not give a crap about K-Pop drama unless it's really really big, like DBSK's breakup or T-ara's scandal. Even then it's not much more than a passing sentiment.
The Korean students in our buddy system for exchange students are aware of how popular K-Pop is abroad, and kind of pityingly judge the exchange students that are still into it, since it's seen as something for younger kids. One exchange student here goes to Inkigayo every week and everyone thinks she's ridiculous.
Only the really popular K-Pop groups and their most popular songs are known to the general public (SNSD, Super Junior, Big Bang, 2NE1, etc). If you look at music charts, you'll see a lot of soloists or other groups dominating. That's who's popular here, people like Akdong Musician, Roy Kim, and Busker Busker. K-Pop is seen as kind of childish and has nowhere near the hype that international fans have constructed. Songs that are popular among the international K-pop community are not necessarily popular here (the most recent Super Junior song anyone knows is Sorry Sorry). That said, it's really popular for younger kids and a lot of foreigners from Asia, the US, and Canada. European exchange students I've met usually aren't as into it. (This is based on a very small pool of people, maybe 60-80 foreign exchange students, so don't get too serious).
Some girl groups still retain a fanbase among horny high school/college aged boys. A Pink came to my university's festival and the guys were going crazy, though no one really knew who they were. SISTAR is just popular because they're sexy.
I Got a Boy was unbelievably popular here. When I arrived in January you would hear it at least four to five times a day just walking around Seoul. Even now you can still hear it while walking past a noraebang or shopping. While the international community didn't seem to care much about Girl's Day's Expectation and Teen Top's Miss Right, they were really popular in Korea and probably the K-Pop songs I heard the most while walking around in Seoul (along with IGAB).
No one cared about Onew's scandals, especially not the smoking part. A large majority of Korean men smoke and it's engrained into the culture. Your bias probably smokes, too. This confirms that the only people upset about Onew dating were his middle school fangirls (for smoking- international fangirls). My Korean language teacher is a SHINee fan and likes Onew; when I asked her what she thought about the scandals she had no idea what I was talking about and was glad that he was dating.
Although people love 2NE1, no one knows or cares about CL's debut. T-ara N4's song is also relatively unknown. 4Minute, contrary to Omona's belief, is extremely popular, and everyone is singing/bringing up What's Your Name.
Jay Park is cool and edgy. Yep.
The general public believed all the T-ara bullying rumors and really dislikes them. At Dream Concert no one really cheered for them, and people around me were cursing and talking shit about them the whole time ("How dare they show their faces" "No one cares about you anymore" "Her face is so swollen" etc). I was sitting in Infinite's section and my friends sitting in SNSD's section heard similar reactions.
Eunjung is nicknamed "ddeok-Eunjung", for the incident in which she shoved ddeok (rice cake) into Hwayoung's mouth, seemingly choking her.
Jiyeon's stripping video may have been hushed from the media, but it's common knowledge and part of the T-ara hatred (and according to my friend, "Most Korean teen boys have seen it."). That coupled with a video in which Jiyeon is telling Hwayoung to mind her own business has made her one of the most hated T-ara members.
This probably won't come as a shock, but Big Bang are highly respected and admired in Korea. They're seen as real artists, not K-Pop idols, by a lot of the public.
The majority of ~edgy~ ~hardcore~ G-Dragon's fanbase is also middle school girls. I went to his concert in Seoul on March 31th and was both shocked by the observation (and embarrassed to be there). I saw maybe two or three guys max and they were all with their girlfriends. There were also several ajummas who brought their children along. There were plenty of empty seats in the audience, and although GD is my bias, the concert was really not that great (though I heard he'd been sick, and apparently he was even worse on the 30th). He wasn't as energetic as Alive Tour in LA and there were really long pauses between stages. He did do an awesome rendition of Bad Boy and Fantastic Baby, though, and Tablo/2NE1 were great.
Lee Hi's fanbase is indeed composed of ajusshis. I went to her private showcase and the ajusshis were all yelling the fanchants even before she came out. It was terrifying and hilarious.
These are just things I've observed after talking to many college-aged Korean students and attending a few K-Pop events (those mentioned above: Dream Concert 2013, G-Dragon's concert, Lee Hi's showcase, and my school festival). Haven't been to a music show. Lemme know if you want receipts.
If you want to know how Koreans see certain aspects of K-Pop, ask away. I'll ask my friends and get back to you.
Source: Me, Korean friends