I guess it's because this part of the story is so dragged. That's also why I said I got impatient. I did consider and understand his side if you can see my comments and replies in the previous chapters, but the whole "misunderstanding" is getting overstretched. Also Dowan has looked at Chamin for so long but he just simply assumes afterwards that Chamin is the kind of person to do that... You'd expect Dowan would know better that Chamin is a good guy, he even said that previously. I'd understand if Dowan just thought and spoke of it in the heat of the moment because of getting hurt but he realized nothing even after cooling down.
Basically this reply is an expanded and explained version to my comment haha

I got a little impatient... How come dowan hasn't and still can't figure out that chamin can't remember?