Why do some keep looking <Kpop Demon Hunters> from an orientalism perspective based on Japan or China?

You all know that the film is basically centered around Korean directors and Korean artists. In X(Twitter) or Instagram, The artists are explaining what Korean cultural context such as actual places, weapons, and patterns, accessories are appear in the movie, with their concept art.

Even art director even instructed Zoey's Shinkal to "never look like Kunai or Shuriken".

So why do many posts try to project images of Japan or China when analyzing images, motifs, stories, etc. of this movie?

For example, there are tons of korean traditional demons which is still not used in this series. Jeoseung Saja is not the only ghost in korea. If you can understand English, you can search Jihaguk Daejeok, Imugi, Dueokshini, Dokkaebi, Gumiho, Geuseunsae, Gangcheori, etc in google. But why some of this subreddit think "Shuten Doji" must be seen in next movie? They think japanese Yokai is fit for mugyo movie?
Frankly, I don't understand. No one wants Chinese monsters like Jiangshi to come out in "Kimetsu no Yaiba" or "Inuyasha," because it's set in a Japanese legend, and there are plenty of monsters that can bring the country's own cultural atmosphere.  Do you they Korean myths and traditional culture alone can't make a series?

And why some think Rumi is Japanese name and her father is japanese demon? If you can read hangul, in the tombstone, Rumi's mother's name is writtern 류미영(Ryu Mi-Young). Rumi's singer name is from her mother's.

And some of them confuses Zoey's Shin-kal as kunai, and Mira's Gokdo as guandao, they say they are japanese and chinese.

Koreans have hated that in past decades, Korea in Western media depicted as strange Chimera combining chinese music, jinbaori, katana, kung fu, geisha and dragon boat, etc. It is the first foreign film to portray Korean traditional culture and art as which real koreans think about themselves, not lens of Japanese or Chinese orientalism.

So, why they keep quoting Japanese folklore, Chinese Jiang-shi that do not even exist in Korean consciousness when analyzing the world, story, and meaning of this mugyo-based movie? If you are not familiar with Korean folktales or legends, shouldn't you search for them first?

Although Jinu plays Bipa, which is influenced from Chinese Pipa, and they eat Ramyeon influenced from Instant Ramen, it doesn't mean that you can treat All of the cultural elements korean culture as same to china or japan.