I mean, it depends on the demographic. It's not mainstream famous, but my mother (in her 50s) is army and watches all the BTS fan stuff. She said she's heard their music in a supermarket before and we also heard something from their most recent album play off a boat when we were at a beach once. I would say most people in their 20s, at least ones who use any kind of social media, know someone who likes kpop and is at least vaguely aware of it. Years ago, I went to BIGBANG's MADE world tour and the attendance was 35k - mostly younger people. On a university campus in Sydney, you would run into tons of people who know kpop. In the rural town I grew up in, which skews towards 50+ people who don't use the internet much and disdain foreign cultures, you would not.
(Context: Australia.)
I think the comparison to anime/manga is interesting. In general, it's considered weird to love foreign media with some exceptions in the high arts (even people who like foreign films are considered weird or pretentious). Anime/manga is very mainstream now, but again, it's pretty much with the younger generations (although the older ones know some of them - eg DBZ/Pokémon - if they had millennial/zoomer children, or just are aware of 'Japanese cartoons'). Obviously generalising, some people are more savvy about media than their cohort. I think it's probably more acceptable to be seriously into kpop here than seriously into anime, as a person who has been both. It's the same thing either way though, kpop fans make friends with kpop friends and anime fans make friends with anime fans.
I do think the Western kpop fandom is generally judged for activity perceived as obsessive, unhealthy, overly consumerist, etc. on social media, just like anime fans are stereotyped as socially awkward, etc. Those stories tend to get attention; it's the same with fans of Western boy bands for instance (and the people that like kpop have quite a lot of overlap with those demographics). So some people who might never have heard a kpop song might know about kpop fans and judge them for that. Also, on Twitter, you can't avoid kpop fans because they tend to post a lot of fancams etc. under unrelated posts to rack up views/spam kpop stuff at people, so that's one way people become aware of them.
I don't think anyone negatively judges Korean people who like kpop any more than they would judge Western people who like Western pop (except for racist reasons, which I acknowledge are very likely in Western countries). The things kpop fans get judged for are for being obsessed with a foreign culture, and for being generally preoccupied with fan culture/obsessed with something to an extreme point, which will get you judged for nearly all hobbies except the most boring ones. Some people judge kpop for stupid reasons, but they tend to judge pop music the same way. My experience with pop music fans (since I like Western pop quite a lot as well as kpop) is that the ones who don't like kpop will typically cite that it is overly manufactured (which is also true of their favourite music) or that they can't connect to music in a language they don't understand very well (a little fairer).
On the whole, society is overly judgmental.
