Looks to me that someone has a bad case of romanticisation.

I'm korean, so I can speak on this; the Korean language is indeed very easy to learn, and the pronunciation and phonetics are pretty specific, but of course we do have our own share of accents as all languages do (well, most I'm sure). For Seo/Suh, they are both one and the same in Korean; the issue here is that for whatever reason, I don't why, but someone decided that when romanizing Korean surnames, they had to have multiple spellings. For example, a common one is Lee, a Korean surname that is actually pronounced with the "L" being totally silent when speaking in Korean, so as a Korean, if I say someone's full name in Korean and they happen to have "Lee" as their last name, the pronunciation in Korean will literally be the sound "-ee", the same sound you would make at the end of 'coffee'. And there are variations of that korean surname in English like Yi. It's weird.