I was also confused by the comparison.
To me Sangwoo was clearly a psychopath that any little thing could end your life. He didn't see others as human but as things. Even when he was ''nice'', it always look like he was waiting for one mistakes to destroy others.
True, Seungho seems to have a short temper, but it's not the same ''anxious'' feeling I get from him. He looks like he can actually feel things or at least reflect on his actions. Granted, he is an ass, but an ass with potential of good.
Right? Like he's more of a spoiled brat than a psychopath. And he is curious about Nak Yeum's "love" for his teacher and I feel like he's yearning for it but doesn't know it yet so he gets all sexual.
That is the feeling I get as well! He's a spoiled brat. I guess with his backstory we'll be able to understand why. Again, I insist on the fact that he is an ass and Nak Yeum deserve to be treat better.
Honestly, at this point, I am more afraid of the teacher. He seems to hide well his intentions and don't care about using others to achieve his own goals. Not caring of the effects on others. He makes me think of Frollo from the hunchback of Notre-Dame ^^' Like he will force you to do horrible stuff and then get mad at you for doing what he asked for...
I read this because Seungho was always compared or put side by side with Sangwoo. I do not feel the same vibes at all. Like Seungho has more of a redemption and Sangwoo literally scares me. The way they treat their ukes as well are very different.