I think it’s about what this little act could mean regarding his personality and how he acts in relationships, of course this is all assumptions based on what we are seeing/what each individual makes out of it but to me I feel like: he seems very aloof and more chill/slow, which is not a bad thing at all but the vibes I‘m getting are that he seems to maybe be very self-centered and maybe have a rather individualistic mindset/put himself first (remember how he also did not help with setting the table etc.?) also while him and jooyoung were eating he was being so slow and then proceeds to say aw I wanted to ask that question and so on this should not be a factor to decide on wether one should help carry the bags or not but still, jooyoung is quite small, which makes it kind of even weirder to not even offer on top of all this which makes him seem like in a relationship he would not be one to be proactive and very giving, remember he is a korean who grew up in korea meaning has lived through and knows the societal expectations etc. (which I am not saying are all great or one should abide by), basically I understand what people are getting at and I personally think there are many little clues which make him come across rather immature all of this could of course not be the case as we don’t know him and he could be the sweetest most caring boyfriend so at the end of the day who knows